U.S. patent application number 09/826602 was filed with the patent office on 2002-07-18 for user interface for a security policy system and method.
Invention is credited to Amador, Jose, Cooper, Geoffrey, Cornwall, Kevin, Shaw, Robert A., Sherlock, Kieran G., Valente, Luis, Wang, Paul.
Application Number | 20020093527 09/826602 |
Document ID | / |
Family ID | 26906795 |
Filed Date | 2002-07-18 |
United States Patent
Application |
20020093527 |
Kind Code |
A1 |
Sherlock, Kieran G. ; et
al. |
July 18, 2002 |
User interface for a security policy system and method
Abstract
A user interface for a network security policy monitoring system
and method that performs network and security assessments based on
system-wide policy, whereby real network traffic is analyzed to
identify abnormalities, vulnerabilities, and incorrect
configurations by listening on a network, logging events, and
taking action.
Inventors: |
Sherlock, Kieran G.; (Palo
Alto, CA) ; Cooper, Geoffrey; (Palo Alto, CA)
; Valente, Luis; (Palo Alto, CA) ; Amador,
Jose; (San Jose, CA) ; Wang, Paul; (San Jose,
CA) ; Shaw, Robert A.; (Los Altos, CA) ;
Cornwall, Kevin; (Poway, CA) |
Correspondence
Address: |
GLENN PATENT GROUP
3475 EDISON WAY
SUITE L
MENLO PARK
CA
94025
US
|
Family ID: |
26906795 |
Appl. No.: |
09/826602 |
Filed: |
April 5, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60212126 |
Jun 16, 2000 |
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Current U.S.
Class: |
715/736 |
Current CPC
Class: |
H04L 41/5012 20130101;
H04L 63/1433 20130101; H04L 43/00 20130101; H04L 43/06 20130101;
H04L 63/083 20130101; H04L 63/1425 20130101; H04L 69/22 20130101;
H04L 63/0227 20130101; H04L 41/0604 20130101; H04L 43/067 20130101;
H04L 43/0811 20130101; H04L 63/0823 20130101; H04L 41/069 20130101;
H04L 63/0263 20130101; H04L 63/1408 20130101; H04L 43/062 20130101;
H04L 41/22 20130101; H04L 63/166 20130101; H04L 41/0893 20130101;
H04L 43/18 20130101 |
Class at
Publication: |
345/736 |
International
Class: |
G09G 005/00 |
Claims
1. A user interface for displaying processed and analyzed network
data to an end user, comprising: a system dashboard kept up to date
with current monitoring information from a monitored network, said
dashboard comprising: a network status console area; a network
events viewing area; and a trend viewing area.
2. The user interface of claim 1, wherein said network status
console area further comprises: an alerts area comprising a FIFO
queue of critical alerts; and a health monitor area showing a
percentage of network traffic that does not violate current traffic
and over a predetermined amount of time.
3. The user interface of claim 1, further comprising: a tear off
status console window for said end user to keep console window open
on a desktop to monitor network status.
4. The user interface of claim 1, using a web page paradigm.
5. The user interface of claim 2, wherein said user alerts are
updated on a real-time basis.
6. The user interface of claim 2, wherein any of said user alerts
links to corresponding alert details information.
7. The user interface of claim 2, wherein the underlying traffic
data of said health monitor is updated automatically at a regular
interval.
8. The user interface of claim 2, wherein severity alerts levels
are distinguished by color codes.
9. The user interface of claim 1, wherein said network events
viewing area further comprises links to any of the following:
summary information; information on all events; and policy history
information; wherein a configurable time period is set.
10. The user interface of claim 9, wherein said configurable time
period comprises any of: a user selected date and time range; last
two hours; today; last 24 hours; yesterday; last seven days; this
month; last month; and last three months.
11. The user interface of claim 1, further comprising any of:
conformance events summary information containing a count of
violations for each rule/disposition pair; violator events summary
information containing a count of the number of violations for each
violating ip-address; and target events summary information
containing a count of the number of violations for each top
destination ip-address.
12. The user interface of claim 11, wherein event summary
information links to network event details information containing
details on events making up said count.
13. The user interface of claim 1, wherein user defined and
configurable query and report settings are stored.
14. The user interface of claim 1, wherein said trend viewing area
further comprises links to network events summary information.
15. The user interface of claim 1, wherein said trend viewing area
further comprises a QuickWeek section, containing any of: a
predetermined number of most frequent rule/disposition combinations
during a past predetermined number of days; a predetermined number
of most frequent violator ip-addresses versus count during said
past predetermined number of days; and a predetermined number of
most frequent target ip-addresses versus count during said past
predetermined number of days.
16. The user interface of claim 1, wherein the trend viewing area
is user customizable.
17. The user interface of claim 1, further comprising embeddable
trend charts into details information, said trend over a time range
dynamically configurable by said end user.
18. The user interface of claim 17, wherein said trend charts
comprise any of: policy effectiveness; number of policy changes
over time; event summary; network event details; and all
conformance counts.
19. The user interface of claim 12, wherein said network event
details information further comprises any of: monitoring point;
disposition name; rule name; disposition code; severity; source
ip-address; source port; destination ip-address; destination port;
ip protocol; event time; and application data.
20. The user interface of claim 19, wherein said application data
comprises any of, but not limited to: ICMP action code; HTTP-URL;
FTP-Filename; SSL-Ciphersuite, Issuer and Subject's certificate
CommonName, Certificate Status; SSH-Authentication handshake
status; and application status code.
21. The user interface of claim 1, further comprising protocol
event details information in context of a particular network event
to a database from which said information is retrieved on an
as-needed basis.
22. The user interface of claim 21, wherein said protocol event
details information further comprises data from attributes.
23. The user interface of claim 22, wherein said data attributes
comprise any of, but not limited to: initiator credential name;
target credential name; rule name for said protocol event; and
disposition name for said protocol event.
24. The user interface of claim 1, further comprising alert event
details information, said information comprising any of: details of
network event that caused alert; rule and disposition name that
triggered alert; log comment from corresponding disposition; time
at which alert was generated; initiator ip address of the
corresponding non-conformant traffic; target ip address of the
corresponding non-conformant traffic; an icon that links to the
network event details page describing the non-conformant network
event; and checkbox to clear alert;
25. The user interface of claim 1, further comprising a policy
update information area showing each time a new policy is
installed, said information comprising: date of policy information;
description of policy; and link to English representation of said
newly installed policy.
26. The user interface of claim 2, further comprising means for
each of said alerts to generate an alert email, said alert email
comprising any of, but not limited to: time said alert occurred;
rule and disposition name that triggered alert; log description
from said corresponding disposition; initiator ip address of
corresponding non-conformant traffic; target ip address of
corresponding non-conformant traffic; and a link to network event
detail, said detail describing said non-conformant network
event.
27. The user interface of claim 26, further comprising a customer
information area allowing said end user to configure a list of
email addresses to receive said alert email.
28. The user interface of claim 1, further comprising means for
ad-hoc querying by said end user.
29. The user interface of claim 28, wherein means for ad-hoc
querying further comprises filtering results by, but not limited to
any or all of: protocol of rule name; policy rule name; regular
expression within rule name; disposition name of violation; regular
expression within disposition name; source ip-address; regular
expression with source ip-address; target ip-address; regular
expression within target ip-address; target port; and regular
expression within target port.
30. The user interface of claim 28, wherein means for ad-hoc
querying further comprises an advanced search feature.
31. The user interface of claim 30, wherein said advanced search
feature is implemented using a dialog box.
32. The user interface of claim 1, further comprising informational
aids, said information aids comprising any of: English language
representation of policy; rule and disposition descriptions; and
copyright information.
33. The user interface of claim 32, wherein said informational aids
are linked to by said end user when said end user places a cursor
over an appropriate field thereby displaying a tooltip of
corresponding descriptions of said fields.
34. The user interface of claim 33, wherein said descriptions are
any of but not limited to: rule descriptions; disposition
descriptions; and Resolved DNS names for ip-addresses; and TCP and
UDP service names.
35. The user interface of claim 33, wherein said informational aids
further comprise any of: context sensitive help;
36. The user interface of claim 1, further comprising a link to
generate a printer friendly printed page.
37. The user interface of claim 1, further comprising displaying
time information in a predetermined time zone.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The invention relates to security and network services. More
particularly, the invention relates to a system and methods for
implementing a system-wide security policy for an entire computer
network, and for providing monitoring and enforcing of computer
network security.
[0003] 2. Description of the Prior Art
[0004] Networked information systems are an essential part of many
organizations. Critical systems, services, and information
resources all require protection that depends on effective
orchestration of a variety of factors: network architecture,
security products, site security, administrative procedures, end
user responsibility, and more. A network security policy is an
explicit plan of how to accomplish this multi-faceted protection,
what objectives the plans should meet, and what assets are being
protected.
[0005] To manage a network, an end user needs to know and
understand what is happening on the network. Most security holes
come from unexpected, misconfigured, or unauthorized services, for
example, from a high-port telnet, a new service added in, a rogue
server, and/or a misconfigured workstation. The end user doesn't
know what is the unauthorized network traffic.
[0006] Security administrators need tools to help them formulate
site security policy and to translate the policy into monitoring
and enforcement mechanisms. They need to be sure that the computer
enforced policy--often cobbled together from a plethora of disjoint
access control mechanisms--matches their enterprise policy, all too
often specified in a loose natural language or a set of unwritten
principles. This leads to confusion as to why access is being
granted or denied to particular resources and may lead to
unintentional breaches of security.
[0007] In addition to monitoring network system traffic, it is
important for network analysts to assess their network's
configuration. A discussion on current techniques for network
assessment follows below.
[0008] A conventional network assessment visit determines the
customer network using the following information:
[0009] 1) Network security scanning technology, e.g. port or
vulnerability scans;
[0010] 2) Customer interviews;
[0011] 3) Inspection of customer log files, perhaps using machine
aggregation and filtering; and
[0012] 4) Occasionally, inspection of customer log files and
network traffic.
[0013] As a matter of practicality, the information is typically
derived from the first three of these items. Customer log files and
network traffic is of a volume so great that it is impractical to
examine it in a short assessment visit.
[0014] The weaknesses such conventional methods are as follows:
[0015] Vulnerability Scans
[0016] Network vulnerability scanners only detect certain types of
known vulnerabilities. Such vulnerabilities are generally not
detected directly, but are inferred based on host responses to a
series of network packets sent to hosts by the scanner. This
process does not directly ensure that data traffic on the subject
network matches expectations, either explicit or implicit.
[0017] Network vulnerability scanners cannot see a host if it does
not respond to packets. A host that is only a source of network
packets, such as, for example, a rogue router, is not visible to a
scanner. Hosts which are turned off or otherwise temporarily
disconnected, such as, for example, workstations and laptops, are
often missed by vulnerability scanners. This problem is compounded
by the fact that scans are often scheduled for non-work hours in
order to alleviate customer fears that the scans will somehow
impact production systems and organizational mission.
[0018] Network scanners typically return a large volume of
vulnerability information, based on all possible configured
elements in a network. The scanner tools cannot currently interpret
those vulnerabilities in light of business requirements which the
subject systems are intended to support, or even for the specific
network architecture of which those systems are a part. The scan
results must be reviewed manually by a security analyst, who
applies his or her knowledge of the business requirements and
network architecture to an interpretation of those results. Such
manual process is error-prone because the volume is so great that
problems may be overlooked.
[0019] Another problem is that the scan derives only
vulnerabilities, not network usage patterns. Therefore, the scan
cannot detect security problems that are attributable to human
behavior, but only those scans that result from misconfigured
systems and/or systems which have documented design problems.
[0020] Network scanners cannot diagnose incorrect client usage of
software. For example, network scanners cannot detect whether web
servers are being used with invalid ciphersuites, whether 40-bit
browsers are in use, and whether a given telnet port is accessed
only by a management station.
[0021] Network scanners must be targeted to particular subnets. If
a customer has forgotten to mention a subnet, the scanner will not
notice it.
[0022] Customer Interviews
[0023] Customers may not provide the network analyst complete or
accurate information, either because the customer forgot details,
because the information is not known to the customer, or because
the customer does not understand the importance of giving the
information to the analyst.
[0024] Customer interviews at best can provide descriptions of
overt usage of subject systems, and generally not covert usage.
Often, formal policies of the organization are not even documented,
much less promulgated, audited and enforced.
[0025] Hidden agendas, office politics, and other factors also can
affect the success of the interview process.
[0026] Host Inspection
[0027] Inspecting host configuration files is a time consuming,
manual process that is subject to human error. In the assessment of
any large network, it is impractical to include an inspection of
the configurations for more than a few critical systems.
[0028] Once again, inspection of host configurations does not
reveal completely intended usage of the subject systems. The
configurations must be analyzed within the context of the business
requirements and overall security environment of the organization.
This manual process is very human dependent and prone to error.
[0029] Log File Inspection
[0030] Log file inspection can provide great insight into the
workings of network components. Machine-based aggregation and
filtering systems can speed this process. However, logs provide
only a components' own view of its status. If a component is
misconfigured, the log data from the component cannot be trusted.
Log data may also be subject to modification by an attacker who has
penetrated the machine and is seeking to mask his presence.
[0031] In addition, since log aggregation systems work in
cooperation with the components that generate the information, they
require configuration changes to every component that they examine.
Also, they are unable to detect when a component is added to the
system.
[0032] Such techniques of performing network assessments generally
are limited in their ability to determine actual security threats
to information systems. Generally, they represent the state of the
art and are indicative of best practices within the security
community today.
[0033] A way to reduce or eliminate the confusion described above
is by providing a user-friendly and, yet, rigorous way of
specifying security policy, as well as providing tools for
monitoring and enforcing the security policy.
[0034] It would be advantageous for a network policy to provide the
definition of normal traffic on the network.
[0035] It would be advantageous to provide a monitoring mechanism
that lets an end user determine and understand traffic and/or
activity on a network.
[0036] It would be advantageous to provide methods and system that,
when given known network characteristics, thereby spots intruder
access, and track changes to a network.
[0037] It would be advantageous to provide a policy generator tool
that assists an end user in generating security policy for a
network.
[0038] It would be advantageous to provide a tool that
automatically converts a network security policy into English
language representation.
[0039] It would be advantageous to provide a tool that allows an
end user to query network traffic data.
[0040] It would be advantageous to provide a technique for
transmitting an event description of network traffic from a source
file or data stream to a target destination, such as a network
policy engine.
SUMMARY OF THE INVENTION
[0041] The invention is a network security policy monitoring system
and method that comprises supportive features, algorithms, and
tools. It is ideally suited for network and security assessments or
long-term monitoring where real network traffic is analyzed to
identify abnormal traffic patterns, system vulnerabilities, and
incorrect configuration of computer systems on the network. The
invention listens on a network, logs events, and takes action, all
in accordance with a rule based system-wide policy. The invention
is able to incorporate external sources of event information, such
as are generated in log files of other network components. The
invention gets protocol information, which can make it more
meaningful to a network administrator.
[0042] The invention sends data upstream to an event log and
interprets the data. it listens to secure protocols and can
identify encryption quality of service parameters. It extracts
basic security parameters, such as, for example, network events,
and passes them to a policy manager component.
[0043] The policy manager component implements system-wide
policies, based on monitored system or enterprise traffic. The
policy manager component provides a trust manager that takes as its
input a security policy defined as a set of policy rules and a set
of credentials, and that is capable of processing requests for
trust decisions, i.e. evaluating compliance with the policy. Unlike
other trust management systems, the invention is designed to be a
passive monitor of network traffic. As such, it need not be
installed on target hosts or integrated into existing
applications.
[0044] Two key aspects of the policy manager component are
provided. One aspect is a unified view of the interaction between
two principals across a stack of protocol areas, each area covered
by discrete policy rules. The final trust decision applied is based
on policy rules that better fit the entire interaction. The second
aspect comprises the policy manager's policy definition language
that supports the monitoring and auditing of a network's activity
in addition to traditional access/denial authorization
decisions.
[0045] The policy definition language is the subject of U.S. patent
application Ser. No. 09/479,781, filed Jan. 7, 2000, entitled, "A
Declarative Language for Specifying A Security". The policy
definition language is discussed herein to the extent necessary to
explain such language to those skilled in the art in connection
with the invention disclosed herein. The declarative language
system comprises a language as a tool for expressing network
security policy in a formalized way. It allows the specification of
security policy across a wide variety of networking layers and
protocols. Using the language, a security administrator assigns a
disposition to each and every network event that can occur in a
data communications network. The event's disposition determines
whether the event is allowed, i.e. conforms to the specified policy
or disallowed and what action, if any, should be taken by a system
monitor in response to that event. Possible actions include, for
example, logging the information into a database, notifying a human
operator, and disrupting the offending network traffic. Further
details of the policy definition language can be found in the
patent application cited herein above.
[0046] Unlike Intrusion Detection Systems (IDS) systems, which look
for the signatures of known attacks, the invention herein is
focused on defining allowed traffic patterns and how to handle
events that deviate from those patterns.
[0047] The invention comprises, but is not limited to, six major
features and tools. The first feature discussed is auto-conversion
of policy language, whereby policy language is converted to an
English language representation. Next, an algorithm for efficient
rule evaluation is provided. Then, a credential/assertion
optimization technique is provided. A policy generator tool is
provided. An embodiment in which the invention is used as an
assessment tool is provided. Finally, a technique for secure
sensitive event extraction from protocol monitoring is
provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0048] FIG. 1a is a schematic diagram of components of the system
according to the invention;
[0049] FIG. 1b is a schematic diagram of components of the system
according to the invention;
[0050] FIG. 2 is a high level workflow flow diagram according to
the invention;
[0051] FIG. 3 is an example of a policy wizard dialog box according
to the invention;
[0052] FIG. 4a is an example of a policy wizard dialog box
according to the invention;
[0053] FIG. 4b is an example of a policy wizard dialog box
according to the invention;
[0054] FIG. 5 is an example of a policy monitor dialog box
according to the invention;
[0055] FIG. 6 is an example of a query tool dialog box according to
the invention;
[0056] FIG. 7 is an example of a query tool dialog box according to
the invention;
[0057] FIG. 8 is an example of a query tool dialog box according to
the invention;
[0058] FIG. 9 is an example of a query tool dialog box according to
the invention;
[0059] FIG. 10a is an example of a policy wizard dialog box
according to the invention;
[0060] FIG. 10b is an example of a policy wizard dialog box
according to the invention;
[0061] FIG. 10c is an example of a policy wizard dialog box
according to the invention;
[0062] FIG. 11 shows a high-level view of an example network
according to the invention;
[0063] FIG. 12 shows an algorithm according to the invention;
[0064] FIG. 13 shows a flow diagram according to the invention;
[0065] FIG. 14 shows an algorithm according to the invention;
[0066] FIG. 15 shows a high level schematic diagram according to
the invention;
[0067] FIG. 16 shows a schematic diagram of process flow according
to the invention;
[0068] FIG. 17 is a block schematic diagram according to the
invention;
[0069] FIG. 18 is a high level flow diagram of the preferred output
section according to the invention;
[0070] FIG. 19 shows a schematic diagram according to the
invention;
[0071] FIG. 20 is an example of a dashboard according to the
invention;
[0072] FIG. 21 shows an example of a tear off console according to
the invention;
[0073] FIG. 22 shows an example of an events summary view according
to the invention;
[0074] FIG. 23 shows an example of a conformance event details page
according to the invention;
[0075] FIG. 24 shows an example of a protocol event details page
according to the invention;
[0076] FIG. 25 shows an example of an events summary page
containing a pop up description according to the invention;
[0077] FIG. 26 shows an example of an events summary page
containing a pop up description according to the invention;
[0078] FIG. 27 shows an example of a conformance event details page
containing a pop up description according to the invention;
[0079] FIG. 28 shows an example of an alert details page according
to the invention;
[0080] FIG. 29 shows an example of a violators chart and table page
according to the invention;
[0081] FIG. 30 shows an example of a targets chart and table page
according to the invention;
[0082] FIG. 31 shows an example of an advanced search dialog box
according to the invention; and
[0083] FIG. 32 shows an example of a link to the advanced search
dialog box according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0084] The invention is a security policy monitoring system and its
supportive features, algorithms, and tools. It is ideally suited
for network and security assessments where real network traffic is
analyzed in order to identify abnormal traffic patterns, system
vulnerabilities and incorrect configuration of computer systems on
the network. The system listens on a network, logs events, and
takes action, all in accordance with a rule based system-wide
policy. The system is able to incorporate external sources of event
information, such as are generated in log files of other network
components. The system gets protocol information, which can make it
more meaningful to a network administrator. The invention sends
data upstream to an event log and interprets the data. The system
listens to secure protocols and can decrypt a session if a key
escrow facility is available. The system extracts basic security
parameters, such as, for example, network events, and passes them
to a policy manager component.
[0085] An important part of understanding the invention is
understanding network security terminology for policy monitoring.
See Table A below.
1TABLE A Terminology Network Event: One complete transaction on the
network, such as a FTP connection or a HTTPS transaction. Each
network event has several component protocol events. Protocol
Event: A transaction at one protocol level. For example, a network
event that represents an FTP connection has protocol events
representing an IP association, a TCP connection, an FTP control
connection, and several FTP control commands. Initiator, Target:
The endpoints of a network event or protocol event. Credential: An
identification of the initiator or target of a protocol event at a
particular protocol level. For lower-level protocols, credentials
are, for example, IP addresses or UDP port numbers. For higher
level protocols, credentials are, for example, user names, file
names, or public key certificates. Association: A placeholder for a
transaction run over a datagram-based protocol such as IP, ICMP or
UDP. The invention herein constructs an association to collect a
conversation between two hosts, or processes in the case of UDP. It
is noted that when the invention misses any data packets between
the two communicating computers, it might not be able to determine
the initiator and the target of the association. Associative array:
A list of value pairs where each associative array entry is indexed
by the first element of its value pair, which is called the key.
Keys are stored in a hash table to make lookups efficient
irrespective of the size of the associative array. Rule: A policy
rule governs a specific interaction, or set of interactions,
between two communicating entities. The invention evaluates policy
rules against protocol events to determine if the latter conform to
the active security policy. Disposition: The policy definition of
what action or state change needs to take place in response to a
network event. Policy Domain: A top level segmentation of a
network, roughly akin to a cloud-like object in a network diagram,
which hides internal detail. Within the policy domain communities
of hosts provide or access services. One community of hosts defines
the limits of the domain. Monitoring Point: A point within a policy
domain where it will be possible to plug a machine into the network
in order to collect packet data. Communities of Hosts: A mechanism
for grouping hosts that have a similar function, e.g. all web
servers or all NT workstations. Perimeter Element: A hardware
device that allows access to and from communities of hosts outside
a policy domain. Examples of perimeter elements are firewalls and
routers. Policy Language: A policy language is used to create a
formal specifi- cation of a network security policy. The preferred
embodiment of the invention incorporates the policy definition
language of U.S. patent application No. 09/479,781, filed 01/07/00,
entitled, "A Declarative Language for Specifying A Security
Policy." It defines first class objects such as rules, credentials
and dispositions. It is based on s-expressions, which are LISP-like
parenthesized expressions. Rogue server: A machine introduced to a
network that is not authorized to be on that network. Rogue router:
An unauthorized router that is added to a network, providing an
alternate path into the network. Typically occurs through
misconfiguration of switches or dialup connections. Real-time
monitoring: Reading packet data off a network and processing it to
events in a stream, so that an event appearing in the network
causes a corresponding event in the stream a short time later. DLL:
Any kind of a dynamically linked library
I. System Overview
[0086] The preferred embodiment of the invention functions by
translating traffic on the network into protocol events that are
themselves combined into network events. As protocol events are
detected, they are compared against a policy. The policy specifies
a disposition of the network event, as defined by the observed
series of protocol events. Information about the protocol events,
the network event and its disposition is stored in a database. This
database of network traffic information can be mined for policy
violations.
[0087] This preferred embodiment of the invention is described with
reference to FIG. 1a. FIG. 1a is a schematic diagram of components
of the system according to the invention. The system comprises a
policy monitoring component 100 that takes as input a policy file
105 that has been generated using a policy generator wizard 110 or
other means, and a file containing network packet dump data 115
that has been collected off of an observed network 125 by a packet
capture 126, or that has been processed by a protocol monitor
processor 127. The system can also process packet event data from
the observed network 125 in a continuous real-time mode, without
first storing packet data to a file.
[0088] The policy monitoring component 100 comprises a policy
manager component 106 that itself comprises a parser 101 for
parsing the policy file 105, a policy engine for 102 for assigning
policy dispositions to network events, and a logger 103 for
determining how to log the information processed by the policy
engine 102, according to an input logging policy 130. It also
comprises a database 104 for storing synthesized information of the
packet dump's 115 conformance to the specified policy 105 performed
by the policy engine 102, where it can be mined with a query tool
135. It also comprises a report script component 160 for querying
the database 104 and creating reports 161, and an alarm script
component 155, for generating alarms based on the severity of the
disposition assigned to network events.
[0089] An equally preferred embodiment of the invention also
comprises a parser tool 150 that takes the policy specification
file 105 as input and automatically generates an English
description of the policy 151 for the end user. The parser tool 150
is optional.
[0090] An equally preferred embodiment of the invention also
provides a secure Web server feature 162 for the end user to review
reports from the end user's host computer 163. The secure Web
server feature 162 comprises the Web server 164 and a report
database 165 that hosts the reports 161 generated using the report
script 160. The Web server feature 162 is optional.
[0091] An equally preferred embodiment of the invention provides
secure management connections (141, 142) and a secure management
host 140 for managing the policy monitoring component 100 and the
combination of the network monitoring components 128,
respectively.
[0092] FIG. 1b shows a simpler embodiment of the invention, wherein
the parser tool 150 and the secure Web server feature 162 are
omitted.
[0093] The default action of the policy engine 102 is that it
denies all traffic. The policy 105 opens holes in this denial to
allow permitted traffic to flow. Although the policy engine 102
assigns a single disposition to an entire network event, the
protocol events are significant. As network data 115 arrives, the
policy engine 102 interprets protocols and generates updates of
protocol event information. The policy 105 is consulted as each new
piece of information arrives, so that the earliest determination of
disposition is reached. For example, if the policy 105 states that
a given IP address may not communicate with another IP address, the
policy 105 can generate a disposition immediately upon receiving
the first packet 115 of the network event.
[0094] To aid policies in early determination of disposition, the
policy language divides dispositions into immediate and final. An
immediate disposition fires immediately, i.e. its value becomes
associated with the network event right away. A final disposition
sets a bookmark to itself as the latest and best disposition. When
all protocol events are processed without an immediate disposition,
the last bookmark set is the disposition that is applied to that
network event. Immediate dispositions are designed to generate
early results and to allow policy writers to issue a definitive
disposition for the network event based on the information received
up to that point. Final dispositions allow for the possibility that
a better disposition might be determined later on, in other words,
allow the policy engine 102 to make a more informed decision based
on additional protocol events that might be received as the network
event progresses.
[0095] Overview of the Components
[0096] An overview of main components of the preferred embodiment
of the invention is discussed below with references to FIG. 1.
[0097] Policy Generator
[0098] The preferred embodiment of the policy generator component
110, also referred to as policy wizard, is a program that makes an
end user readily able to generate a first-pass policy for a new
site. Policy information is input into a set of dialog boxes and a
policy is generated. The wizard enables the end user to generate
policy based on what can be considered gross characteristics of a
network at the IP level, such as, for example, policy domains,
communities of hosts, servers, subnets and firewalls, as well as at
the UDP/TCP service level (for example, communities of hosts that
can access certain services on server hosts).
[0099] Once a policy has been generated with the wizard, it is
output in the policy specification language 105 so that it may be
directly processed by the policy monitor component 100. The policy
wizard 110 is also able to save files at the wizard level, i.e.
such that the policy may be refined in the wizard and
regenerated.
[0100] Policy Monitor
[0101] The policy monitoring component 100 comprises a suitable
user interface such as an MFC-based front end or a command line
interface, and the policy manager 106. The policy manager 106
performs the actual examination of a sequence of event updates
stored in a file or transmitted in a continuous stream 115 in the
context of a policy specification 105 and signals the adherence to
the policy via records written to the database 104.
[0102] Network Monitor
[0103] The network monitor component 127 provides the following
capabilities:
[0104] Streams-based interpretation of packet dump data 126 in, for
example, DMP format; and
[0105] Packet- and connection-based textual logging of protocol
information. Logging is selectable by protocol and may be enabled
only for one or more connections. In another embodiment of the
invention, the network monitor 127 can perform serialization of
event data. That is, the network monitor 106 can process a packet
capture file 126 into a series of event updates that contain only
the salient security details for processing by the policy monitor
100. The resulting file is significantly smaller than the original,
for example, approximately {fraction (1/20)}.sup.th to {fraction
(1/100)}.sup.th the size of the original. It is also possible for
sensitive data, such as passwords and documents, to be removed from
the file. However, it should be appreciated that the original
packet capture file is needed to perform full analysis.
[0106] In another embodiment of the invention, the network monitor
127 can read packet data directly from observed network 125,
generating a continuous stream of event updates for the policy
monitor 100. This stream operates in real-time so that the policy
monitor 100 processes events shortly after they happen on observed
network 125.
[0107] It should be noted that the network monitor 127 can be used
as a standalone tool, but typically is invoked from within the
policy monitor component 100 and the query tool 135 in normal
operation of the invention.
[0108] It should also be noted that the network monitor and the
policy monitor may run on the same machine.
[0109] For a more detailed discussion on the internals of the
network monitor, refer to section, VI. Network Monitor Internals
Descriptions, herein below.
[0110] Query Tool
[0111] The query tool 135 allows the end user to view the data that
has been stored in the database 104 by the policy manager 106.
[0112] Policy Compiler
[0113] The policy compiler performs syntactic and semantic checking
of a policy specification. Upon successful compilation the compiler
as controlled by runtime arguments, may:
[0114] generate a DLL containing a compilation of credential and
condition verification code; and
[0115] generate a pseudo-english report that summarizes the
policy.
[0116] It should be appreciated that it is not necessary to run the
compiler because the policy monitor component will automatically
compile and install a policy from the policy specification
file.
[0117] Platform
[0118] The policy generator 110 runs on a Windows NT or Unix
machine while the policy monitor 100 and the network monitor 127
run on Linux machine(s). It should be appreciated that these
components can run equally well on other suitable operating
systems. In addition to policy and network monitoring software, the
following software components are also installed on the appropriate
machines:
[0119] Microsoft Visual C++6.0;
[0120] SybaseASE 11.9.2; and
[0121] NT NDIS packet drivers and Windump 2.0.
[0122] It should be appreciated that these components can run
equally well on other compilers, databases, and packet monitoring
systems.
[0123] Policy Files
[0124] There are two file types that are used within the
invention's environment, and are described below in Table B.
2TABLE B File Type Suffix Description Policy wizard File .spw
Intermediate file used by the policy wizard to store policy
information between invocations. Policy monitor File .spm Output
file generated by the policy wizard and used as the policy input
into the policy monitor. Contains a description of the policy in
the policy language.
[0125] The preferred embodiment of the invention incorporates a
high level workflow method for developing policy, as follows:
[0126] 1) Creating an initial policy using the policy generator
tool;
[0127] 2) Uploading the policy file to a remote machine;
[0128] 3) During the initial policy development phase, running the
network monitor to collect traffic, and the policy monitor to
analyze traffic separately, as follows:
[0129] a) Running the network monitor and specifying an output file
of the collected traffic, and possibly specifying via parameter a
limit to the number of packets captured, e.g. 50,000;
[0130] b) Running the policy monitor to analyze traffic collected
by specifying the file containing the collected traffic;
[0131] 4) Examining the output of the policy monitor run by
querying the database using the query tool;
[0132] 5) Modifying the policy as needed using the policy generator
tool; and
[0133] 6) Repeating steps 2 through 5 until a comprehensive desired
policy is defined. At this point the end user may start monitoring
network traffic on a continuous basis, and using generated reports
as input for further policy refinement.
[0134] High Level Workflow Example
[0135] The high level workflow described above can be illustrated
further by understanding an example, as follows. System components
of the invention are referenced using FIG. 1. Screen interactions
are described with reference to the preferred embodiment of the
invention. Other screen displays with similar function might
equally well embody the invention.
[0136] Referring to FIG. 2, an initial policy is generated (201).
Often the initial policy is created from corporate network policy,
in whatever form that may take, and a network topology diagram. For
the sake of this example, it is assumed that the policy wizard 110
was used to generate an initial, simple policy 105.
[0137] Next, compliance of current network traffic to this initial
policy is monitored (202). Such monitoring is achieved by
collecting packet information off the network and running such data
115 against the initial policy 105 using the policy monitor
100.
[0138] Then the query tool 135 is used to data-mine output network
event data from the database 104, using the mined data to check for
traffic that is not consistent with the policy 105, and reporting
the results (203).
[0139] Once anomalies have been found, the next step is to work out
where the problem lies. The problem could be network equipment is
misconfigured and needs to be corrected (203); otherwise acceptable
behavior is not covered currently by the policy specification file
the file needs to be corrected (204); or, otherwise acceptable
behavior is not covered currently by the corporate policy and the
corporate policy needs to be corrected (205). In the case of this
example, it is assumed that the policy specification 105 is
incomplete and an end user needs to add a new rule to permit the
observed traffic pattern.
[0140] Generate a Policy Specification File From a Wizard
Policy
[0141] The end user starts the policy generator tool, or wizard
110, by double clicking on a policy wizard shortcut on the end
user's desktop. In the preferred embodiment, a window such as
depicted in FIG. 3 opens.
[0142] In this example, the end user has opened a file,
c:.backslash.spm.backslash.quickstart.backslash.null.spw, through
the File.fwdarw.Open menu item 301. This file contains a very
simple policy that defines a single policy domain defined by a
10.0.0.0/8 subnet mask. Rules within this policy deny essentially
all traffic.
[0143] The end user chooses to compile the policy, whereby the
dialog box in FIG. 4 opens. The end user presses the "Process
Policy" button 401 and a file named null.spm in the output file
exntry field 402 is generated and saved.
[0144] FIG. 4b shows the dialog box in FIG. 4a with printed results
from the compile process in a text window 403.
[0145] File Running Policy Monitor Over Canned Data
[0146] The end user starts the policy monitor 100 by double
clicking on a policy monitor shortcut on the desktop. In the
preferred embodiment, a window such as depicted in FIG. 5
opens.
[0147] The end user ensures that the "Input Dump File" entry field
501 points to a data dump file, here qs.dmp, and that the "Policy"
entry field 502 points to the null.spm (monitor) file that the end
user generated above. The "Monitoring Point" entry field 503 is
derived from a policy domain name "Intranet" that is present in the
null.spw (wizard) file.
[0148] The end user ensures database connectivity information is
set correctly. The ODBC entry field 504 with entry "sybase" points
to a Sybase database running on a local machine. The username
"policy" 505 with some password, shown as "******" 506 have been
preinstalled.
[0149] The end user presses the Run button 507 and the .dmp file is
processed through the policy specification file 105 placing the
output data into the database 104.
[0150] Look at the Results Using Query Tool
[0151] The end user starts the query tool 135 by double clicking on
a query tool shortcut on the desktop. In the preferred embodiment,
a window such as depicted in FIG. 6 opens.
[0152] The end user presses a "Network Events" button 601 and the
dialog box depicted in FIG. 7 appears. FIG. 7 is a dialog box that
allows the end user to enter login information for the database
104.
[0153] Here the end user enters the same username and password as
was used in policy monitor 100 and connects to a database 104 named
Policy on localhost.
[0154] When connected, the screen shown in FIG. 8 appears. FIG. 8
is a dialog box that allows the user to select which processed
network data to view from database 104. The topmost entry in the
"Execution Run" pull-down contains most recent data was added to
the database 104. In this case it is current processing of the
qs.dmp file. The end user presses the "Query" button and network
event information for this run is retrieved from the database 104
and shown in as in FIG. 9.
[0155] FIG. 9 shows a queried rule view dialog box according to the
preferred embodiment of the invention. FIG. 9 shows that the
null.spw policy has denied all traffic. The network events having
disposition Udp_Access_Denied represent DNS lookups from an
internal host (10.5.63.143) to another internal host (10.5.63.6).
It is assumed for this example that this is traffic conforming to
policy, and therefore the end user adds a rule to the policy to
permit this event.
[0156] Add a New Rule Using The Wizard
[0157] The end user returns to the policy wizard main window and
presses the "Edit Rules" button which opens a dialog box as shown
in FIG. 10a. FIG. 10a shows a dialog box for generating a new rule
according to the invention. The end user selects the "Intranet"
domain from the "Policy Domain" pull-down to add a rule for our
Intranet domain. The end user types a rule name, such as
Internal_Dns into the "Rule Name" field and presses the "New"
button. The end user selects the communities and services to which
this rule applies. For simplicity in this example, the end user
wants to allow DNS from any internal nodes to any other internal
nodes and therefore selects an Initiator community of hosts
Inside_Nodes, a service of DNS, and a Target community of hosts
Inside_Nodes. The end user then presses the "Add Selected" button
for each in turn to create a rule as shown in FIG. 10b, where FIG.
10b shows a dialog box for generating a new rule according to the
preferred embodiment of the invention.
[0158] Next the end user generates a new policy specification file
and runs policy monitor. The end user returns to the query tool and
presses the "Network Events" button again to get a new rule view
dialog box. The topmost "Execution Run" is now the output from the
processing just completed. The end user presses the "Query" button
and can now see that DNS traffic from 10.5.63.143 to 10.5.63.6 is
now conformant to the policy as shown in FIG. 10c, where FIG. 10c
shows the communities of the policy specification.
DETAILED DESCRIPTION OF COMPONENTS
[0159] The preferred embodiment of the invention incorporates the
following components, detailed description of which follows
below.
A. The Policy Generator Tool
[0160] The preferred embodiment of the invention provides a policy
generator tool, or simply policy generator, equally referred to as
policy wizard, that provides a level of abstraction on top of the
policy language, and which simplifies the process of creating an
initial policy based on gross characteristics of a network at the
IP level, such as policy domains, communities of hosts, servers,
subnets, firewalls.
[0161] The policy generator provides a novel mechanism for
translating desired network security policy, such as corporate
network security policy, into a policy specification file that can
be interpreted and implemented by a policy monitor mechanism.
[0162] Building a policy with the policy wizard involves: deciding
on logical divisions within the network, i.e. policy domains,
grouping network nodes into logical communities, and expressing
rules about which communities of hosts can provide what services to
which communities of hosts.
[0163] High Level View of Policy Generation
[0164] The first step in building a basic policy is to define a
high-level topology for the network. Not much detail is necessary.
In the preferred embodiment of the invention, the network needs to
be divided into bounded units called policy domains. In practice,
the choice of a policy domain boundary is fairly obvious. Usually
natural logical and physical boundaries in a network help define
policy domain boundaries. For example, firewalls and routers with
packet filters commonly denote the important boundaries. When
defining a simple policy, it is reasonable to ignore switches,
bridges, hubs, and routers that connect interior subnets.
[0165] It is suggested that policy domains be as small as required
by traffic monitoring limitations and as large as specification of
rules allow. Rules are written about traffic visible in a policy
domain. Traffic in a policy domain is logically considered to be
visible anywhere within the policy domain even though networking
elements, such as, for example, switches prevent such visibility in
most networks. By writing rules about traffic as though it is
visible anywhere within the policy domain, the same set of rules
can be applied to network traffic anywhere within the policy
domain.
[0166] It has been found that if a policy domain is too small,
rules need to be duplicated for each extraneous policy domain. If a
policy domain is too large, then the choice of a network traffic
monitoring point can become overly constrained, or the ability to
detect IP spoofing and rogue routers is lost.
[0167] Identify the Policy Domains
[0168] FIG. 11 shows a high-level view of an example network. An
Intranet 1101 is connected to a DMZ 1102 through a firewall 1103.
The DMZ 1102, in turn, connects through a router 1104 to the
Internet 1105 and through a second router 1106 to an external
corporate network 1107. In this example, an end user is only
expected to be able to monitor traffic in the Intranet and DMZ, so
these two entities are declared to be policy domains. Rules in the
policy will only apply to allowed traffic in the DMZ and Intranet.
The corporate network and Internet are viewed only as communities
of hosts visible from within the policy domains.
[0169] It should be appreciated that the end user could choose to
declare the Internet and Corporate network to be policy domains,
but, by doing so, would only create unnecessary work because the
end user does not intend to monitor traffic there. Any rules
generated would thus never be used.
[0170] Add Perimeter Elements
[0171] In the preferred embodiment of the invention, the point of
connection of a policy domain to the outside world is known as a
perimeter element. For each perimeter element the set of nodes
visible through it needs to be known and, for generating rules to
detect IP spoofing and rogue routers, the MAC address of the
perimeter element itself needs to be known.
[0172] As an example, if an end user could sit inside a policy
domain and look out through boundaries, it is probable that the end
user would see a filtered version of what is on the other side.
Network address translation (NAT) can change the IP addresses seen
though the boundary. For example, a proxying firewall may not let
the end user see anything directly beyond a single IP address at
the boundary. Filters may limit the view to only a few hosts when
thousands are actually present.
[0173] Define Communities
[0174] In the preferred embodiment of the invention, communities
consist of sets of IP addresses. They can be expressed as, for
example, individual IP addresses, ranges of addresses, or subnet
masks. Additionally, communities can be composed of other
communities. It is often the case that a community of nodes
involves all nodes in some existing set except for a node or two.
Communities are defined in terms of included elements and excluded
elements.
[0175] Define Rules For Each Policy Domain
[0176] In the preferred embodiment of the invention, rules defined
for a policy domain describe allowed transactions. For example, if
no rules are written, the policy specifies that everything at the
IP level or above is denied, although this specification is not
strictly true because typically auto-generated rules that apply to
IP broadcast traffic and ICMP traffic within the policy domain
exist. Rules create holes in this base layer that declares all
traffic illegal.
[0177] Rules are defined in terms of initiator communities, target
communities, and the services allowed. Services consist of a set of
port numbers and indicators of whether TCP or UDP protocols are
used.
[0178] Using the Policy Generator
[0179] The preferred embodiment of the invention provides a front
end for the policy generator. It provides a user interface for
entering and editing a simple policy. The front end reads and
writes the current state of a policy from or to an intermediate
file. The currently preferred extension for the intermediate file
is .spw. When a policy has been specified to the satisfaction of
the end user, it is written to an intermediate policy file for
processing by the policy generator backend that generates a formal
policy specification file compatible with the policy monitoring
system.
[0180] The front end allows the end user to edit policy domains,
communities, services, and rules, to read and write the current
policy from or to an intermediate file, and to process the
intermediate policy file into the formal policy specification
file.
[0181] The preferred embodiment of the invention allows several
instances of each editing process to be open simultaneously. The
interaction is intended to feel very live. Data changed in one
editing process should be reflected in the contents shown in other
editing processes. For example, if a community is added in one
community editing process, then it is immediately available for use
in all editing processes. When building a policy, entities are
first created, then filled in. From the time of creation they can
be used throughout the policy. Consequently, a community or policy
domain does not need to be fully specified in order to be used.
However, to prevent errors in backend processing, all entities
should be complete before the intermediate policy file is submitted
to the backend for policy specification file generation.
[0182] In the preferred embodiment, only one policy is under
development at any time. The front end starts up containing a
default policy that is empty except for some predefined default
services. This policy can be used as a starting point or an
existing policy can be read from a saved intermediate policy
file.
[0183] It has been found that it is best to use simple names in
developing a policy and to use a name that makes sense from a
predetermined point of reference, not a fully qualified name that
makes sense from any point of reference. For example, it is better
to give a rule a short, descriptive name such as,
"Allow_Outgoing_Mail" than to give the rule a long name such as,
"Allow_Mail_From_Intranet_To_Outside_Intranet".
[0184] For an in-depth understanding of the formal policy
specification generated by the policy generator, or policy wizard,
please refer to the section, Understanding the Wizard Generated
Policy, below.
B. Collecting Packet Data
[0185] The preferred embodiment of the packet gathering component
128 is a program referred to as the harvester. It reads packets off
the observed network 125 and writes them to either a packet capture
file 126 or to a TCP socket that is connected to the policy monitor
100.
[0186] As an example, the harvester reads packets off the network
when invoked as follows:
[0187] harvester -i eth0 -c 1000-dump qs.dmp
[0188] In this example, 1000 packets are read from a network
interface labeled `eth0` and stored in file `qs.dmp.`
[0189] The harvester can also be configured to read packet data and
convert it to event data suitable for policy monitor 100. As an
example, the harvester may be invoked as follows:
[0190] harvester -i eth0 -c 1000-enc qs.dme
[0191] In this example, 1000 packets are read off the network
interface labeled `eth0`, converted to event data suitable for
policy monitor 100, and stored in the file `qs.dme`.
[0192] The harvester can also be configured to read packet data,
convert it to event data suitable for policy monitor 100, and
stream such data directly to the policy monitor in real time. As an
example, the harvester may be invoked as follows:
[0193] harvester-i eth0 -c 1000-enc 10.5.63.6:333
[0194] In this example, 1000 packets are read off the network
interface labeled `eth0`, converted to event data suitable for
policy monitor 100, and transmitted in a TCP network stream to port
333 on the machine with IP address 10.5.63.6. This machine and TCP
port may be configured so that the policy monitor 100 reads the
data and processes it.
[0195] It should be appreciated that the events are transmitted as
they are processed, so that the policy monitor 100 is able to see
events shortly after they occur on the observed network 125.
[0196] In this mode of operation, the policy monitor 100 is also
able to pass information about policy dispositions back to the
harvester. The harvester can use this information to make
processing of packets more efficient. For example, if the policy
monitor 100 has determined that a given network event is acceptable
according to the policy, the monitor can sometimes expedite its
protocol processing by skipping packets until the network event
terminates.
C. Policy Monitor
[0197] The preferred embodiment of the invention provides a policy
monitor component that provides a user interface, either graphical
or command line, that allows the configuration of various options
of the monitor, policy engine and logger.
[0198] Monitor Configuration
[0199] Monitor configuration allows the end user to configure the
location of the input packet dump, policy to be used, and the
specification of the monitoring point.
[0200] The Input dump file specifies the input file, in tcpdump
format that is to be used.
[0201] The Policy input specifies the .spm file that contains the
policy specification to be used.
[0202] The Monitoring Point is a specification of where the Input
dump file was collected. This name is derived from policy domain
names that are specified in the policy wizard. For example, if a
packet dump was collected in a policy domain named "Intranet" then
the Monitoring Point name INTRANET_MONITOR should be used.
[0203] Monitor Logging Options
[0204] The monitor logging options allow the end user control of
the location and the amount of data that gets written to the
backend database.
[0205] The Execution Run Comment field allows the entry of freeform
text that is added to the logs in the database to help identify
this particular run of policy monitor.
[0206] ODBC Name provides the name of the ODBC source to which
output data will be written. The DB Username and DB password are
the end user's database login information. The Save Password allows
the program to save the password in the clear so that it will not
need to be entered the next time the program is run.
[0207] Output Options
[0208] Output options allow the end user to specify whether the
trace output from the monitor should be displayed in a console
window (Output to console) or sent to a file (Output to file:).
[0209] Advanced Options
[0210] Advanced options allow more options to be set. In day to day
operation, it is rare that such options need to be changed.
[0211] Advanced Monitor Configuration
[0212] An Assert DLL parameter allows specification of the name of
the DLL to be used to verify condition and credential assertions.
Note that if this DLL does not match the version of the policy
specified then this DLL will be regenerated, overwriting the
provided DLL.
[0213] A Trace Options parameter allows the end user to provide
configuration of runtime trace options. This option affects the
amount of output generated by the monitor. For a more efficient
operation, this field should be left blank.
[0214] A Certificate Dir argument points to a directory that
contains trusted CA root certificates in DER encoded form.
[0215] Advanced Packet Logging Options
[0216] The packet logging options section allows the configuration
of the trace options to be provided by the low level packet
monitor. The various logging options may be specified at a global
level (by setting them for layer "-All-") or individually on a
per-layer basis. Again it is to be noted that specifying logging
options will adversely affect the performance of the monitor.
[0217] The Site Handle parameter specifies a name that is
associated with the particular company or site that is being
monitored. It is used to segment a table that is used for
ip-address name resolution within the output database.
[0218] Advanced Monitor Logging Options
[0219] The Disable Logging checkbox disables the writing of all
logging data to the database. If logging is enabled then the
remaining checkboxes provide for the enabling or disabling of the
logging of network events with the given final disposition code.
For example, if Disable Logging is not selected and only Policy
Error selected then the only network events that are logged to the
database are those that resulted in a final disposition code of
POLICY_ERROR.
[0220] During normal operation information about all protocol
events within a network event is logged, even those that occurred
after a final disposition was reached. An Enable All Layer Logging
parameter can control this feature. When set on, all protocol
events are logged to the database. When not set only those protocol
events that are processed before a disposition is reached are
logged.
D. QueryTool
[0221] The preferred embodiment of the invention provides a query
tool to examine the data that was placed in the database. The
preferred query tool allows the following functions to be
performed:
[0222] Examining network events, such as protocol events, that are
contained within the execution runs in the database;
[0223] Examining IP Connectivity for execution runs in the
database;
[0224] Editing and making user defined SQL queries to the
database;
[0225] Performing forward and reverse DNS lookups (using the
current DNS configuration);
[0226] Viewing policy monitoring run information from the database,
and selecting a default run for further viewing;
[0227] Explicitly connecting to a specific database; and
[0228] Turning on/off IP address to hostname resolution.
E. Other Tools
[0229] The preferred embodiment of the invention provides other
tools discussed below.
[0230] Compiler
[0231] In its simplest form the compiler needs just a single
argument that is the input policy specification file. This form is
often all that is needed while doing initial development of a
policy. It should be appreciated that the compiler is rarely used
in standalone form since its function, with the except ion of the
-r flag, is subsumed into the policy monitor component.
[0232] Example Usage
[0233] During initial development a command such as the following
could be used while getting rid of syntactic and semantic errors
from the policy under development:
[0234] pmsCompiler.exe security.pms
[0235] Once compiler errors are gone, the end user is ready to
generate pieces that are used to run the policy monitor. For
example, the end user can use the command line:
[0236] pmsCompiler.exe -d verify security.pms
[0237] that compiles the security policy, and generates a
verification DLL named "verify.dll".
[0238] Compiler Options
[0239] The following arguments in Table D may be provided to the
example pmsCompiler.exe.
3 TABLE D pmsCompiler -? -r -c <cxx-file>-d <dll-file>
<policy-file>*
[0240] -c <cxx-file>
[0241] Generate Credential and Condition assertion verification
code to the named file. The suffix ".cxx" will be appended to the
name that is provided. This option will rarely be used to allows
the end user to look at the actual code that will be used to verify
assertions.
[0242] -d <dll-file>
[0243] Generate a DLL containing the assertion verification code to
the named file. The suffix ".dll" will be appended to the name that
is provided. If the -d flag is used without the -c flag then the
source code will be written to a temporary file. This option is
often used to generate the assertion verification DLL. The
alternative is to allow the runtime Policy Monitor to generate the
DLL for itself.
[0244] -r
[0245] Generate a pseudo-english description of the policy to
stdout. The output of this command would be a useful starting point
for a policy report to a customer.
[0246] -?
[0247] Display a usage string.
[0248] <policy-file>
[0249] The required policy specification (".pms") file.
[0250] -b <db-name>
[0251] Store information about the compiled policy in the named
database. db-name is the name of a user data source that has been
configured within Control Panels.fwdarw.ODBC. This argument is
rarely used. The alternative is to allow the runtime Policy Monitor
to write the policy to the database if needed.
[0252] -o <output-file>
[0253] Redirect compiler messages to stdout to the named output
file. Rarely used.
[0254] -t <trace-opts>
[0255] Enable debug tracing. For more specific details try
providing the argument "-t ?". This option will be rarely used
since it only provides information to allow debugging of the
compiler itself.
[0256] -v
[0257] Use VisualC++ to preprocess macros rather than the internal
preprocessor. This overrides the -n option. This option will be
rarely used.
[0258] -g
[0259] Add debug trace code (i.e. printf statements) to the
generated Credential and Condition verification code. The generated
code will also be compiled with symbol information (the C compiler
-g flag). This option will be rarely used.
[0260] -n
[0261] Do not run a preprocessor. C preprocessor macros such as
#define and #include may be included within a policy file. This
option specifies that the pre-compiler should not be run prior to
actually compiling. This option will be rarely used.
[0262] -z
[0263] Output the dump output of the parsed policy. This output
looks remarkably similar to the input file with the comments
stripped and some component definitions reordered.
[0264] Network Monitor
[0265] The preferred embodiment provides a streams-based network
monitor that can be run in a standalone mode independent of the
policy monitor. In this way it can be used to provide a detailed,
streams-based view of the network traffic, or a subset thereof. For
example, run in standalone mode is desirable when a particular
protocol is not supported natively by the policy monitor and an end
user desires to see raw data to gain an understanding of what is
going on.
[0266] It should be appreciated that a convenient way of accessing
such functionality is through the query tool.
[0267] Example Usage
[0268] The following invocation of the network monitor:
[0269] mon -ev 2-I ALL=all
C:.backslash.spm.backslash.quickstart.backslash- .qs.dmp
[0270] examines the qs.dmp file, producing extremely verbose output
for event 2 only.
[0271] Table E provides a list of network monitor options according
to the invention.
4TABLE E Monitor Options mon [-log
LAYER[=[-]option1,[-]option2...]]* [-n npkt] [-skip pkt] [-until
endpkt] [-ev eventID] [-untilev eventid] [-justev eventid]
[-noclients] dump_file -log -n npkt Only process the first npkt
packets from the input data. -skip pkt Skip pkt packets before
beginning to process the input data. -until endpkt Only process
data through the packet number provided is reached -ev eventID Only
process the data starting at the given eventID. -untilev eventid
Only process the data through eventid. Note that in order to find
the end of eventid, events with ids greater than eventid may be
processed. -justev eventid Only process the data for eventid. Note
that in order to find the end of eventid, events with ids greater
than eventid may be processed. This option is the equivalent of -ev
eventId -untilev eventId. -noclients Do not generate any output for
higher level protocols such as HTTP, FTP, etc. dump_file The dump
file, in tcpdump/windump format, that contains the input data.
[0272] Understanding the Wizard Generated Policy
[0273] Using the Policy Generation Wizard, a user specifies a
network security policy in terms of the network services provided
by certain hosts to other hosts in the network. When such policy is
processed, the wizard generates a formal and more detailed
description of the network security policy using the policy
language. The policy language specification may then be used to
analyze network traffic using the policy monitor tool. The results
of this analysis can be studied using the query tool. An exemplary
policy language is taught in A Declarative Language for Specifying
a Security Policy, patent application Ser. No. 09/479,781 filed on
Jan. 7, 2000.
[0274] Understanding the output of the preferred query tool
requires understanding how the preferred wizard translates the
high-level view of security policy it presents to its users into a
set of policy language objects such as rules, credentials and
dispositions.
[0275] Understanding the policy generation process involves the
following:
[0276] Understanding the predefined rules, credentials and
dispositions;
[0277] Understanding the implicit rules and credentials; and
[0278] Understanding the explicit rules and credentials.
[0279] Predefined Rules, Credentials and Dispositions
[0280] Every policy generated by the wizard includes a set of
predefined default rules for handling protocol events that do not
conform to the user-defined policy i.e. rules that deny access, as
well as rules for handling common network events not covered by the
user policy. These rules and their dispositions are shown in Table
F and Table G, and further discussed below.
5 TABLE F Rule Protocol - Action Disposition Ip_Deny IP - all
Ip_Access_Denied Icmp_Deny ICMP - all Icmp_Access_Denied Udp_Deny
UDP - all Udp_Access_Denied Tcp_Deny TCP - all Tcp_Access_Denied
Http_Deny HTTP - all Http_Access_Denied Ftp_Deny FTP - all
Ftp_Access_Denied Ssl_Deny SSL - all Ssl_Access_Denied Ssh_Deny SSH
- all Ssh_Access_Denied
[0281] Table G shows the default rules for all the protocols
supported by the policy monitor. The policy engine selects these
rules when no other rule can be found that is satisfied by the
protocol event.
6TABLE G Rule Protocol - Action Disposition Ip_Deny_Pure_Ip IP -
PROTOCOL_UNKNOWN Deny_Pure_Ip Tcp_Missed_Connections TCP -
MISSED_CONNECT Warn_Missed_Tcp_Connect Ftp_Ignore_Data_Connections
FTP - DATA_OPEN ok
[0282] Table H below shows rules that cover protocol events not
addressed by the wizard's user interface. These are well understood
events that can be separated from those handled by the default
rules. Ip_Deny_Pure_Ip is assigned to IP associations whose payload
is not one of the three well-known IP-based protocols (ICMP, UDP
and TCP). Tcp_Missed_Connections is assigned to network events
where the establishment of the TCP connection was not witnessed by
the policy monitor. Ftp_Ignore_Data_Connections is assigned to all
FTP data connections which, from a security policy monitoring
perspective, can be safely ignored. It is noted that the preferred
policy wizard generates other rules to deal with common protocol
events as discussed below.
[0283] Table H shows the predefined dispositions used by all the
rules in the generated policy. Associated with each disposition are
its disposition code and severity, which may be used in the query
tool to filter network events.
7TABLE H Disposition Disposition Code Disposition Severity ok OK
None policy-error POLICY_ERROR CRITICAL Ip_Access_Denied
ACCESS_DENIED HIGH Deny_Pure_Ip ACCESS_DENIED HIGH
Monitor_Broadcasts OK MONITOR Icmp_Access_Denied ACCESS_DENIED HIGH
Monitor_Icmp OK MONITOR Udp_Access_Denied ACCESS_DENIED HIGH
Tcp_Access_Denied ACCESS_DENIED HIGH Warn_Missed_Tcp_Connect OK
WARNING Ftp_Access_Denied ACCESS_DENIED HIGH Http_Access_Denied
ACCESS_DENIED HIGH Ssl_Access_Denied ACCESS_DENIED HIGH
Ssh_Access_Denied ACCESS_DENIED HIGH
[0284] It should be noted that ok and policy-error are actually
built-in dispositions in the policy language. If policy-error is
encountered it indicates an error in the processing of either the
policy or the network traffic data by the policy monitor. The
meaning of the other dispositions is explained later in this
document in the context of the rules in which they are used.
[0285] Finally, the wizard includes a set of predefined credentials
that are combined with dynamically generated credentials and used
in implicitly generated rules:
[0286] _Multicast_Addresses--a set of commonly used IP multicast
addresses;
[0287] _Local Broadcast Address--the IP address used for
non-directed local broadcasts (255.255.255.255); and
[0288] _Zero_Ip_Address--a zero-valued IP address (0.0.0.0),
commonly used by BOOTP clients;
[0289] It is noted that the double underscore prefix in these
credential names is used to ensure that there aren't any name
conflicts with credentials generated to represent user-defined
communities and services.
[0290] Explicit Rules and Credentials
[0291] Every community defined by the user results in a credential
of the same name. Because the scope of a community name is that of
the entire policy specification, the resulting credential names
need not be massaged to ensure uniqueness.
[0292] Service names are also global in scope. Because services and
communities share the same name space, every service defined in the
policy results in a credential whose name is constructed by
prefixing the user-supplied service name with the underscore
character. Thus, for example, the Smb service is represented by a
credential named _Smb.
[0293] Rule names, on the other hand, are only unique within the
scope of a policy domain. Furthermore, if a user-defined rule
addresses a service that is both a UDP and a TCP service, the
wizard generates two rules, one for the UDP protocol and another
for the TCP protocol. Thus, a rule name is constructed by prefixing
the user-supplied name with the protocol name (Udp_ or Tcp_) and
the policy domain name.
[0294] For example, if the user defines a rule titled Smb_Services
within a policy domain named Intranet, the wizard will generate two
rules, Udp_lntranet_Smb_Services and Tcp_lntranet_Smb_Services, for
the UDP and TCP protocols respectively.
[0295] User-defined rules may also result in the generation of
additional credentials. When defining a rule, the user provides the
following information:
[0296] Zero, one or more initiator communities;
[0297] Zero, one or more services; and
[0298] Zero, one or more target communities.
[0299] If more than one initiator community are specified, the
wizard generates a credential that combines these communities into
a union. The credential name is constructed by appending the word
_Initiator to the user-supplied rule name, prefixed by the policy
domain name. Using the example above, the wizard would create a
credential named Intranet_Smb_Services_Initiator.
[0300] Likewise, if more than one target communities are specified,
the wizard creates a credential representing their union and names
it by appending the word _Target to the policy domain and rule
names e.g. Intranet_Smb_Services_Target).
[0301] However, if one or more services are specified they are
combined with the target credentials according to the service type.
For example, the Smb service (for the SMB protocol suite) and its
like-named credential include ports that are used for both TCP and
UDP. Thus, for the Smb_Services rule used above, the wizard would
generate the following additional credentials:
[0302] Udp_Intranet_Smb_Services_Target and
[0303] Tcp_Intranet_Smb_Services_Target. These credentials combine
Intranet_Smb_Services_Target (or a single target community) with
the _Smb credential and constitute the actual target credentials
used in Udp Intranet_Smb_Services and Tcp Intranet_Smb_Services
respectively. It should be noted that, in many cases, the set of
UDP and TCP services referenced in a rule will have little, if any
overlap.
[0304] Of course, if the end user does not specify any services the
wizard uses the Intranet_Smb_Services_Target credential (or a
single target community credential) to identify the target
principal.
[0305] Implicit Rules and Credentials
[0306] For each policy domain within the policy specification, the
wizard automatically generates a set of rules and credentials that
define the valid IP-level traffic seen at the monitoring point
within the domain. In addition, an ICMP rule is generated that
handles all intradomain ICMP traffic, as well as a credential for
the monitoring point in that domain.
[0307] The monitoring point credential is based on an agent
descriptor string manufactured by the wizard. The agent descriptor
is constructed by converting the policy domain name to uppercase
and appending to it the word _MONITOR. Thus, for example, a policy
domain named Intranet is assigned the agent descriptor:
[0308] INTRANET_MONITOR.
[0309] Note that this is the agent descriptor to be used in the
policy monitor when analyzing data collected at this monitoring
point.
[0310] The monitoring point credential itself is named by appending
the word _Monitors to the policy domain's name. In the example
above, the credential would be named Intranet_Monitors.
[0311] The wizard segregates all intradomain ICMP traffic (common
on an enterprise network) by means of a rule that assigns it the
disposition Monitor_Icmp. The rule is named by combining the
protocol name with the domain name using the word _Within. For
example, in the Intranet policy domain the rule would be named
Icmp_Within_Intranet.
[0312] IP traffic is described by a set of rules that
systematically enumerate all valid IP-level traffic within the
policy domain, between hosts in the policy domain and external
hosts, and between external hosts through the policy domain (when
more than one perimeter element is present). Most of these rules
provisionally allow IP traffic, letting the subsequent protocol
layers (ICMP, UDP, TCP, etc.) determine if the traffic is indeed
allowed either by a user-defined (explicit) rule or by a predefined
rule.
[0313] The first IP rule provisionally allows all intradomain IP
traffic. It is named by combining the protocol name with the domain
name using the word _Within (e.g., Ip_Within_Intranet). In the
absence of a higher-level protocol within an intradomain IP
association, the rule assigns the network event a disposition of
Deny_Pure_Ip (i.e., its final outcome).
[0314] The intradomain IP rule uses the policy domain's defining
community as its target principal. However, it generates another
credential to be used as the initiator. This credential combines
the defining community with the predefined credential for
zero-valued IP addresses (_Zero_Ip_Address). The generated
credential is named by appending the word Initiator to the
generated rule name (e.g., Ip_Within_Intranet_Initi- ator.
[0315] Another intradomain IP rule is used to segregate typical
broadcast and multicast traffic within an enterprise network. It is
named by combining the protocol name with the domain name using the
words _Broadcasts_Within (e.g., Ip_Broadcasts_Within_Intranet). Its
initiator principal is the same as that used for the general
intradomain traffic e.g. Ip_Within_Intranet_Initiator). Its target
is a new credential constructed by combining the predefined
credentials _Multicast_Addresses and _Local_Broadcast_Address with
the directed broadcast addresses for all the subnets within the
policy domain's defining community. The new credential is named by
appending the word _Target to the rule name e.g.
Ip_Broadcasts_Within_Intranet_Target).
[0316] The intradomain broadcast and multicast traffic is assigned
the disposition Monitor_Broadcasts.
[0317] Traffic between hosts in the policy domain and external
hosts is described by a set of rules whose complexity depends on
how much information the user supplied about the topology of the
network. Specifically, it depends on how many perimeter elements
were specified and on whether or not the interface addresses, i.e.
MAC addresses, of the perimeter elements are included in the policy
specification.
[0318] If there are external communities associated with at least
one perimeter element for which the interface address is not known,
the wizard generates a credential combining all such communities in
a single union unless there is only one such community, in which
case its credential already exists. This credential is named by
combining the policy domain name with the string
_External_Communities (e.g., Intranet_External_Communities).
[0319] The wizard then generates two rules defining the traffic
between hosts internal to the policy domain and these external
communities. The wizard names these rules by combining the protocol
name with the domain name and the string _To_External_Communities
or _External_Communities_To, depending on the direction of the IP
traffic (e.g., Ip_Intranet_To_External_Communities for outbound
traffic and Ip_External_Communities_To_Intranet for inbound
traffic).
[0320] The credentials used alternately as the initiator and target
principals for these rules are the policy domain's defining
community and the aforementioned credential for the external
communities. The rules provisionally allow the IP traffic to flow,
subject to other rules for higher level protocols. In the absence
of a higher-level protocol within the network event, the rule
assigns it a disposition of Deny_Pure_Ip, i.e. its final
outcome.
[0321] External communities visible through one or more perimeter
elements whose interface addresses are known, are handled by a
separate set of rules, two per perimeter element. For each
perimeter element, the wizard starts by creating a credential that
combines the credential(s) for the external community(ies) visible
through it with the perimeter element's interface address. Such
credential is named by combining the domain name with the perimeter
element name and the string _Communities. For example, external
communities visible through a perimeter element named Firewall
would be described by a credential named
Intranet_Firewall_Communities.
[0322] The wizard then generates two rules defining the traffic
between hosts internal to the policy domain and the external
communities visible through this perimeter element. The wizard
names these rules by combining the protocol name, the domain name,
the perimeter element name and the word _To (e.g.,
Ip_Intranet_To_Intranet_Firewall for outbound traffic and
Ip_Intranet_Firewall_To_Intranet for inbound traffic).
[0323] The credentials used alternately as the initiator and target
principals for these rules are the policy domain's defining
community and the aforementioned credential for the external
communities. The rules provisionally allow the IP traffic to flow,
subject to other rules for higher level protocols. In the absence
of a higher-level protocol within the network event, the rule
assigns it a disposition of Deny_Pure_Ip, i.e., its final
outcome.
[0324] Finally, if there is more than one perimeter element
associated with the policy domain, the wizard generates rule-pairs
that describe the traffic between external communities visible
through specific perimeter elements as well as external communities
visible through any perimeter element, i.e. those without
associated interface addresses. The rules are named by combining
the names of each pair of perimeter elements with the protocol
name, the policy domain name and with the word _To, in the case of
addressable perimeter elements, or with the string
_External_Communities, for all other external communities. An
additional rule is generated to cover traffic between external
communities not associated with an addressable perimeter element
and is named by combining the protocol name with the domain name
and the string _Between_External_Communities.
[0325] Thus, if the Intranet domain used as an example in this
section were to have a second (addressable) perimeter element named
Router and a third non-addressable perimeter element (whose name is
unimportant), the wizard would generate the following rules to
cover all traffic amongst their respective external
communities:
[0326] Ip_Intranet_Firewall_To_Intranet_Router
[0327] Ip_Intranet_Router_To_Intranet_Firewall
[0328] Ip_Intranet_Firewall_To_External_Communities
[0329] Ip_External_Communities_To_intranet_Firewall
[0330] Ip_Intranet_Router_To_External_Communities
[0331] Ip_External_Communities_To_Intranet_Router
[0332] Ip_Intranet_Between_External_Communities
[0333] Table I and Table J summarize all the implicit rules and
credentials generated for the example policy domain Intranet. The
policy domain includes two perimeter elements with a specified
interface address (Firewall and Router) and a third non-addressable
perimeter element.
8TABLE I Credential Comment Intranet_Monitors Uses agent descriptor
INTRANET_MONITOR Ip_Within_Intranet_Initiator Defining community
plus zero-valued IP address Ip_Broadcasts_Within_Intranet Combines
standard multicast _Target addresses with local broadcast and
directed broadcast addresses Intranet_External_Communities Combines
all external communities not associated with addressable perimeter
elements Intranet_Firewall_Communities Combines all external
communities visible through the Firewall perimeter element
Intranet_Router_Communities Combines all external communities
visible through the Router perimeter element
[0334]
9TABLE J Credentials Disposition (I - Initiator (I - Immediate Rule
T - Target) F - Final) Ip_Within_Intranet I:
Ip_Within_Intranet_Initiator I: continue T: Intranet F:
Deny_Pure_Ip Ip_Broadcasts_Within_Intranet I:
Ip_Within_Intranet_Initiator I: T: Monitor_Broadcasts
Ip_Broadcasts_Within_Intranet_Target Icmp_Within_Intranet I: none
(ignore) I: Monitor_Icmp T: none (ignore) Note: uses
Ip_Within_Intranet as prerequisite Ip_Intranet_To_External-
_Communities I: Intranet I: continue T: Intranet_External_Communit-
ies F: Deny_Pure_Ip Ip_External_Communities_To_Intranet I:
Intranet_External_Communities I: continue T: Intranet F:
Deny_Pure_Ip Ip_Intranet_To_Intranet_Firewall I: Intranet I:
continue T: Intranet_Firewall_Communities F: Deny_Pure_Ip
Ip_Intranet_Firewall_To_Intranet I: Intranet_Firewall_Communities
I: continue T: Intranet F: Deny_Pure_Ip
Ip_Intranet_To_Intranet_Router I: Intranet I: continue T:
Intranet_Router_Communities F: Deny_Pure_Ip
Ip_Intranet_Router_To_Intranet I: Intranet_Router_Communities I:
continue T: Intranet F: Deny_Pure_Ip
Ip_Intranet_Firewall_To_Intran- et_Router I:
Intranet_Firewall_Communities I: continue T:
Intranet_Router_Communities F: Deny_Pure_Ip
Ip_Intranet_Router_To_Intranet_Firewall I:
Intranet_Router_Communities I: continue T:
Intranet_Firewall_Communities F: Deny_Pure_Ip
Ip_Intranet_Firewall_To_External_Communities I:
Intranet_Firewall_Communi- ties I: continue T:
Intranet_External_Communities F: Deny_Pure_Ip
Ip_External_Communities_To_Intranet_Firewall I:
Intranet_External_Communities I: continue T:
Intranet_Firewall_Communities F: Deny_Pure_Ip
Ip_Intranet_Router_To_External_Communities I:
Intranet_Router_Communities I: continue T:
Intranet_External_Communities F: Deny_Pure_Ip
Ip_External_Communities_To_Intranet_Router I:
Intranet_External_Communi- ties I: continue T:
Intranet_Router_Communities F: Deny_Pure_Ip
Ip_Intranet_Between_External_Communities I:
Intranet_External_Communi- ties I: continue T:
Intranet_External_Communities F: Deny_Pure_Ip
[0335] Logging and Reporting Modules
[0336] The preferred embodiment of the invention provides logging
and reporting modules, as described herein with reference to FIG.
1a. As the policy engine module 102 reaches dispositions on network
events, it passes the network event object to the logging module
103.
[0337] The preferred embodiment of the invention also provides an
alarm script 155. As the policy engine module 102 reaches
dispositions on network events of a certain disposition severity,
for example, CRITICAL or HIGH, the alarm script is invoked to
provide expedited alerting of the disposition.
[0338] The following algorithm is used to enter the data into the
database 104.
[0339] During initialization of the logging module 103, the
database 104 is tested to see if it contains a policy that matches
the MD5 hash of the policy 105 currently being used by the policy
engine 102. If no such policy is found then the policy details are
added to the database 104;
[0340] with each network event passed to the logging module 103, if
logging of network events is enabled, then:
[0341] if the final disposition of the network event matches one of
the list of dispositions that is to be logged, then:
[0342] add the network event to the buffer of network events,
flushing the buffer to the database 104 if it is full;
[0343] loop through each of the protocol events contained in the
network event;
[0344] if the initiator and responder principals have not been
already added to the database 104 then do so, caching the database
keys for later use; and
[0345] add the protocol event to the buffer of network events,
flushing the buffer to the database 104 if it is full.
[0346] On a periodic basis report statistics 161 are sent across a
secure channel to a secure, customer accessible server 162. The
preferred embodiment of the invention uses the following
algorithm.
[0347] A report script 160 described is used to generate a report
161 for the configured or predetermined time period. An example of
a list of preferred acquired or calculated statistics or
intermediate steps is contained in Table K below;
[0348] The report 161 is then packaged using the tar command and
PGP to encrypt the resulting file using the public key of a
recipient email account; and
[0349] This encrypted file is then emailed to the recipient email
account.
[0350] It should be appreciated that an equally preferred
embodiment performs name resolution on packet data after the packet
data has been collected, rather than concurrent with collecting the
packet data. An advantage to such name resolution technique is that
name resolution after collection is removed from real-time
processing, thereby rendering name resolution more efficient.
[0351] On the receiving secure server 162 the following algorithm
is invoked on the received email message.
[0352] PGP is used to decrypt the received encrypted tar file;
[0353] Tar is used to extract the report data;
[0354] The report data is then processed to link the report into
the reporting website 164 for the client; and
[0355] Any supplied protocol event data is then stored in a
reporting database 165.
[0356] Upon accessing the reporting website 164 the client is able
to peruse the reports that have been generated, access the protocol
event data stored in the database 165 via a cgi script.
10TABLE K Generate network events in subsidiary web files, based on
execution run; Generate network events table, Generate table for
URL's and status codes; Find events of interest; Check for all
execution runs being in sequence; Give best optimization for
queries; Compute number of events and number of exceptions; Apply
definitions of log severity and disposition code in order of
criticality; Apply query to several execution runs at a time,
collect results; Select key disposition and key policy rule first,
to be able to find distinct disposition and policy rule; Determine
sort order for disposition and policy rule table; and Generate a
list of dispositions in the selected events, counting how many
events were generated by each.
II. Automated Generation of an English Language Representation of a
Formal Network Security Policy Specification
[0357] The preferred embodiment of the invention uses a formal
specification of network security policy that is to be enforced on
a network. This specification provides a precise, compact
description of network security policy. However, it is difficult
for a layperson to understand. In order to allow comprehension of
the policy by non-technical staff within a user's organization the
parser module (FIG. 1 150) is used to generate an English language
description of the policy. This description is simple enough to be
understood, yet captures the salient details of the policy.
[0358] The preferred embodiment of the invention provides the
following algorithm for generating the English language
representation. The algorithm comprises the following:
[0359] Loading the policy into the parser from its text
representation; and
[0360] Looping through all supported protocols, from the highest
level protocols to the lowest;
[0361] Sorting the rules for this protocol into ranked order;
and
[0362] Looping through these rules from the highest ranking to the
lowest;
[0363] Generating a text description of the rule using the
algorithm below. If an HTML flag has been set then format the text
into a HTML table; and
[0364] Append this description to a collection of descriptions
already generated.
[0365] The preferred embodiment of the invention provides the
following rule algorithm to generate an English language
representation of a single policy language rule. The algorithm is
described with reference to FIG. 12. The algorithm outputs the name
of the rule at hand (2001). It then proceeds to output the agent's
name (2002), where the agent is the subject network monitor(s) to
which the policy applies. The algorithm then loops through all
protocol and action combinations (2003). If the action is to be
ignored (2004), then the rule applies to the whole protocol (2005).
Otherwise, the rule applies to certain actions only (2014). The
algorithm then looks at the immediate outcome for the rule (2006).
The algorithm then outputs the corresponding directive for the
outcome (2007). If any conditions exist on the disposition, then
the algorithm outputs the conditions (2008). The algorithm looks at
the final outcome (2011), then outputs the corresponding final
outcome of the rule (2012). If any conditions exist on the
disposition, then the algorithm outputs the conditions (2013). If
the rule applies to a particular initiator or target, then the
algorithm outputs the initiator or target name (2009). Otherwise,
the algorithm outputs a general inclusive name, such as, for
example, "anyone."
[0366] The algorithm then checks for prerequisites (2010). If any
are discovered, the algorithm then outputs such prerequisites.
[0367] For an example of the rule algorithm discussed above, Table
L below shows code to the example implementation.
11TABLE L if (isBuiltin( )) return; Bool processedImmediate =
false; Bool immediateDefaultContinue = false; Bool capitalize =
true; string str; string protocol; //output the table row start if
(html) str = ".backslash.n<tr><p>"; else str =
".backslash.n.backslash.n"; //output the rule name if (html) str+=
"<TD WIDTH=.backslash."10%.backslash."VALIGN=
V.backslash."TOP.backslas- h."><B>" + getName( ) + "<a
name =.backslash."" + getName( ) +
".backslash."></B></B></TD>"; else str +=
"Rule" + getName( ) + ":"; // output the agent name string
agentName; if (getAgent( ) == 0) agentName = "All Monitors"; else
agentName = getAgent( ) -> getName( ); if (html) str += "<TD
WIDTH=
.backslash."5%.backslash."VALIGN=.backslash."TOP.backslash.">" +
agentName + "</TD>"; // start the cell for the description if
(html) str += "<TD WIDTH=.backslash."85%.backslash."VAL-
IGN=.backslash."TOP.backslash.">"; // loop through the protocol
and action combinations Bool first = true; for
(PrsUnion::const_iterator t0 = protocol->begin( ); t0 !=
_protocol->end( ); t0++) { for (PrsUnion::const_iterator t2 =
_action->begin( ); t2!= action->end( ); t2++) { if (first)
first = false; else protocol += ","; //if the action is ignore then
it applies to the whole protocol it
((*t2)->getStringRepresentation( ) !=PrsConst::META_IGNORE)
protocol +=(*t0)->getStringRepresentation( ) + "-" +
(*t2)->getStringRepresentation( ) + " "; else protocol +=
(*t0)->getStringRepresentation( ) + " "; .backslash.} } //look
at the outcome to figure what we do with this traffic //is there an
immediate clause if (_immediate != 0) { // output text based on the
code string code = _immediate->getDefault( )->getCode( ); if
(code == PrsConst::DISPCODE_OK) { capitalize ? str += "Allow" str
+= "allow"; capitalize = false; } else if (code ==
PrsConst::DISPCODE_CONTINUE) { if (_final->getDefault(
)->getCode( ) == PrsConst::DISPCODE_OK) capitalize ? str +=
"Provisionally allow" : str += "provisionally allow"; else if
(_final->getDefault( )->getCode( ) == "POLICY_ERROR") ;//say
nothing . . . this is the default else capitalize ? str +=
"Provisionally deny" : str += "provisionally deny";
immediateDefaultContinue = true; } else { capitalize ? str +=
"Deny" : str += "deny"; capitalize = false; } str += protocol; if
((_immediate->getGuards( ) != 0 &&
(_immediate~>getGuards( )->size( ) != 0)) /* KGS &&
!immediateDefaultContinue */ { if (_immediate->getGuards(
)->size( ) == 1) str += "with condition ("; else str += "with
conditions ("; first = true; for
(std::vector<PrsGuardedDisposition*>:: const_iterator cond =
_immediate->getGuards( )- >begin( ); cond !=
_immediate->getGuards( )->end( ); cond++) { if (first) first
= false; else str += ","; if (html) str += "<I>"; str +=
(*cond)->getGuard( )->getName( ); if (html) str +=
"</I>"; } str += "), "; .backslash.} processedImmediate =
true; } //is there a final clause if (_final != 0) { if
(!processedImmediate) { // output text based on the code string
code = final->getDefault( )->getCode( ); if (code ==
PrsConst::DISPCODE_OK) { capitalize ? str += "Provisionally allow"
: str += "provisionally allow"; capitalize = false; } else if (code
== "POLICY_ERROR") ;//say nothing . . . this is the default else {
capitalize ? str += "Provisionally deny" : str += "provisionally
deny"; capitalize = false; } str += protocol; if
((_final->getGuards( )) != 0 && (_final->getGuards(
)->size( ) != 0)) { if (_final->getGuards( )->size( ) ==
1) str += "with condition ("; else str += "with conditions ("; Bool
first = true; for (std::vector<PrsGuardedDispos- ition*>::
const_iterator cond = _immediate->getGuards( )- >begin( );
cond != _immediate->getGuards( )->end( ); cond++) { if
(first) first = false; else str += ","; if (html) str +=
"<I>"; str += (*cond)->getGuard( )->getName( ); if
(html) str += "</I>"; } str += "), "; } } else { // output
text based on the code string code = _final->getDefault(
)->getCode( ); if (!immediateDefaultContinue) { if (code ==
PrsConst::DISPCODE_OK) str += "but provisionally allow"; else if
(code == "POLICY_ERROR") ; // say nothing . . . this is the default
else str += "but provisionally deny"; } if ((_final->getGuards(
)) != 0 && (_final->getGuards( )->size( ) != 0)) {
str += "with conditions ("; Bool first = true; for
(std::vector<PrsGuardedDisposition">:- : const_iterator cond
= _immediate->getGuards( )- >begin( ); cond !=
_immediate->getGuards( )->end( ); cond++) { if (first) first
= false; else str += ","; if (html) str += "<I>"; str +=
("cond)->getGuard( )->getName( ); if (html) str+=
"</I>"; } str += "), "; } .backslash.} } if (html) str +=
"from <I>" +(_initiator->getCredential( ) ?
_initiator->getCredential( )-> getName( ) "anyone")
+"</I> to <I>" +(_target->getCredential( ) ?
_target->getCredential( )-> getName( ) : "anyone")
+"</I>"; else str += "from" +(_initiator->getCredential(
)? _initiator-> getCredential( )->getName( ) : "anyone")
+"t0" +(_target->getCredential( )? _target-> getCredential(
)->getName( ) : "anyone"); if (getPrerequisite( ) != 0) { str +=
", provided that"; Bool first = true; for (vector<const
PrsRule*>::const_iterator t3 = _prerequisite->begin( ); t3 !=
_prerequisite->end( ); t3++) { if (first) first = false; else
str += "or"; if (html) str += "<I><a href=.backslash."#" +
(*t3)->getName( ) + ".backslash.">" + (*t3)->getName( ) +
"</a></I>"; else str += (*t3)->getName( );
.backslash.} .backslash.str += "is true.", } // start the cell for
the description if (html) str += "</TD></TR>"; else str
+="(Agent" + agentName + ")."; osfm << str.c_str( );
[0368] For an example of an output file generated by the main
algorithm discussed above, Table M shows the example of the output
in table format. (For an example of a policy specification file
that can be used as input into the main algorithm discussed above,
refer to Table R below.)
12TABLE M Rules for protocol HTTP Http_Blocked_Service_Violation
All Deny HTTP from anyone to anyone, Monitors provided that Tcp
Blocked Services is true. Http_Deny All Deny HTTP from anyone to
anyone Monitors Rules for protocol FTP
Ftp_Blocked_Service_Violation All Deny from anyone to anyone,
Monitors provided that Tcp Blocked Services is true. Ftp_Deny All
Deny FTP from anyone to anyone Monitors
Ftp_Anonymous_Authentication All Allow FTP-CONTROL_AUTHENTICATE
Monitors with condition (Authentication_Rejected), from Anon_User
to anyone Ftp_Validate_Password All Allow FTP-CONTROL_AUTHENTICATE
Monitors with conditions (Authentication_Rejected,
Strong_Password), from anyone to anyone Ftp_Ignore_Data_Connections
All Allow FTP-DATA_OPEN from anyone to Monitors anyone Rules for
protocol SSH Ssh_Validate_Handshake All Monitors Allow
SSH-HANDSHAKE, SSH- SESSION_ABORTED with conditions
(Ssh_Authentication_Failed, Ssh_Authentication_Aborted,
Ssh_Secure_Authentication_Modes), from anyone to anyone
Ssh_Blocked_Service_Violation All Monitors Deny SSH from anyone to
anyone, provided that Tcp Blocked Services is true. Ssh_Deny All
Monitors Deny SSH from anyone to anyone Rules for protocol SSL
Ssl_Validate_Handshake All Monitors Allow SSL-HANDSHAKE with
conditions (Authentication Rejected, Ssl_Session_Qos), from anyone
to anyone Ssl_Blocked_Service_Violation All Monitors Deny SSL from
anyone to anyone, provided that Tcp Blocked Services is true.
Ssl_Deny All Monitors Deny SSL from anyone to anyone
Ssl_Missed_Handshakes All Monitors Allow SSL-MISSED_HANDSHAKE from
anyone to anyone Rules for protocol TCP
Tcp_Blocked_Services_Response All Monitors Deny TCP-ABORT,
TCP-CLOSE, TCP- TIMEOUT with condition (Tcp_Data_Xfer), from anyone
to anyone, provided that Tcp Blocked Services is true.
Tcp_Connection_Terminated All Monitors Allow TCP-ABORT, TCP-CLOSE,
TCP- TIMEOUT from anyone to anyone Tcp_Deny All Monitors
Provisionally deny TCP from anyone to anyone
Tcp_X_Shh_From_Clouds_To_Cgi X_Monitors Provisionally allow
TCP-CONNECT from _Provisional Clouds to
Tcp_X_Shh_From_Clouds_To_Cgi- _Provi sional_Target
Tcp_X_Spm_Colloc_Traffic X_Monitors Allow TCP-CONNECT from Modin to
Tcp_X_Spm_Colloc_Traffic_Target Tcp_X_Spm_Colloc_Traffic_Provis
X_Monitors Provisionally allow TCP-CONNECT from ional Modin to
Tcp_X_Spm_Colloc_Traffic- _Provisional_ Target
Tcp_X_Ssh_From_Monkey_To_Flu X_Monitors Provisionally allow
TCP-CONNECT from ffy_Provisional Monkey to
Tcp_X_Ssh_From_Monkey_To_Fluffy_Pr ovisional_Target
Tcp_X_X_Loghost_Traffic X_Monitors Allow TCP-CONNECT from
X_Web_Servers to Tcp_X_X_Loghost_Traffic_Target
Tcp_X_Dns_From_Colloc_To_Dns X_Monitors TCP-CONNECT from _Server
X_Coloc_Subnet to Tcp_X_Dns_From_Colloc_To_Dns_Serve r_Target
Tcp_X_Port_1984_Traffic X_Monitors Allow TCP-CONNECT from
X_Coloc_Subnet to Tcp_X_Port_1984_Traffic_Target
Tcp_X_Ssh_To_Web_Server X_Monitors Allow TCP-CONNECT from
X_Ssh_To.sub.-- Web_Server_Initiator to Tcp_X_Ssh_To.sub.--
Web_Server_Target Tcp_X_Ssh_From_Fluffy_To_Monk X_Monitors
Provisionally allow TCP-CONNECT from ey_Provisional Fluffy to
Tcp_X_Ssh_From_Fluffy_To_Monkey_Pr ovisional_Target
Tcp_X_Ssh_From_X_To_X_Web_S X_Monitors Provisionally allow
TCP-CONNECT from ervers_Provisional
X_Ssh_From_X_To_X_Web_Servers_Pr visional_Initiator to
Tcp_X_Ssh_From_X_To_X_Web_Server s_Provisional_Target
Tcp_X_Http_From_Any_To_All_We X_Monitors Provisionally allow
TCP-CONNECT from b_Servers_Provisional anyone to
Tcp_X_Http_From_Any_To_All_Web_Ser vers_Provisional_Target
Tcp_X_Stmp_From_All_To_X X_Monitors Allow TCP-CONNECT from
X_Stmp_From_All_To_X_Initiator to _Smtp Tcp_Blocked_Services All
Monitors Provisionally deny TCP-CONNECT from anyone to anyone
Tcp_Missed_Connections All Monitors Allow TCP-MISSED_CONNECT from
anyone to anyone Tcp_Blocked_Services_Violation All Monitors Deny
TCP-PROTOCOL_UNKNOWN from anyone to anyone, provided that Tcp
Blocked Services is true. Tcp_Unknown_Protocol All Monitors Deny
TCP-PROTOCOL_UNKNOWN from anyone to anyone Rules for protocol UDP
Udp_X_Dns_From_Colloc_To_Dn X_Monitors Allow UDP-ASSOCIATION from
s_Server X_Coloc_Subnet to Udp_X_Dns_From_Colloc_To_Dns_Serv
er_Target Udp_Deny All Monitors Deny UDP from anyone to anyone
Rules for protocol ICMP Icmp_Within_X X_Monitors Allow
ICMP-ASSOCIATION from anyone to anyone, provided that Ip Within X
is true. Icmp_Deny All Monitors Deny ICMP from anyone to anyone
Rules for protocol IP Ip_Directed_Broadcasts_Within.sub.--
X_Monitors Allow IP-ASSOCIATION from X Ip_Within_X_Initiator to
Ip_Directed_Broadcasts_Within_X_Target Ip_External_Communities_To_-
X X_Monitors Provisionally deny IP-ASSOCIATION from
X_External_Communities to X_Coloc_Subnet
Ip_X_To_External_Communities X_Monitors Provisionally deny
IP-ASSOCIATION from X_Coloc_Subnet to X_External_Communities
Ip_Within_X X_Monitors Provisionally deny IP-ASSOCIATION from
Ip_Within_X_Initiator to X_Coloc_Subnet Ip_Non_Directed_Broadcasts-
_Wit X_Monitors Allow IP-ASSOCIATION from hin_X
Ip_Within_X_Initiator to _Generic_Multicast_And_Broadcast_Addr
esses Ap_Deny All Deny IP from anyone to anyone Monitors
Ip_Unknown_Protocol All Deny IP-PROTOCOL_UNKNOWN from Monitors
anyone to anyone
III. Algorithm for Efficient Rule Evaluation
[0369] The preferred embodiment of the invention comprises a
technique for a policy engine internally to organize policy rules
in order to effect an efficient evaluation of protocol events at
runtime. Evaluation of a protocol event entails selecting one or
more applicable policy rules using an evaluation algorithm. The
preferred evaluation algorithm is described on pages 75 through 77
in A Declarative Language for Specifying a Security Policy, patent
application No. 09/479,781 filed on Jan. 7, 2000. An excerpt
describing the preferred evaluation algorithm is provided below in
Table S.
[0370] Using this technique, policy rules are organized in a manner
that minimizes the number of rules that need to be considered when
determining the set of rules applicable to a given protocol event.
The algorithm is described with reference to FIG. 13 as
follows:
[0371] Create a first associative array, such as, for example,
agent-to-protocols, where the key is an agent descriptor and the
value is a reference to a second associative array with all the
policy rules applicable to network traffic monitored by that agent
(3001);
[0372] Create a second associative array, such as, for example,
protocol-to-actions, where the key is a protocol name and the value
is a reference to a third associative array with all the policy
rules applicable to that protocol (3002).
[0373] Create a third associative array, such as, for example,
action-to-rules, where the key is a protocol action and the value
is a list of references to the policy rules applicable to that
protocol action (3003). The rules referenced in this list (3004)
are sorted in decreasing order of rank number, taking into account
any constraints, such as, for example, rank-above, that might be
present. Rules with the same rank number are ordered in the lexical
order of their names.
[0374] It should be noted that the same rule can be referenced by
different lists of ordered rules and, in each list, can have
different rank numbers because the ranking of a rule is relative to
the ranking of the other rules in the same list.
IV. Assessment Tool
[0375] The preferred embodiment of the invention provides an
assessment tool that allows the discussed technique for
continuously assessing the security of a system to be applicable to
both long-term and short-term network assessment. The tool provides
an additional dimension to network assessment. That is, it provides
the ability to capture and classify large volumes of network
traffic efficiently, based on a formal policy which describes
permitted traffic. The tool adds network usage to the known list of
features discussed in an assessment framework.
[0376] It has been found through field experience that the
invention can be useful in the following contexts:
[0377] Identifying services that were not mentioned by the system
administration staff of a network that is being assessed;
[0378] Identifying usage patterns of critical machines. In an
assessment framework, this applies to typical usage patterns,
because a long-term deployment of the invention is needed to
continuously analyze and monitor changes in usage or rare aberrant
behavior;
[0379] Identifying services; and
[0380] Analyze routing patterns. It should be appreciated that
subnets are not scanned.
[0381] It should be appreciated that using the invention as a
supplemental process in performing network assessments results in
the following benefits:
[0382] Rather than providing an inference of possible network
behavior that is based on what hosts are configured to do, the
network behavior is directly analyzed based on direct observation
of data traffic;
[0383] Rather than basing security analysis on a static snap-shot
of the network environment as it existed at a particular moment,
the analysis is based on a dynamic recording of network behavior
over some non-trivial amount of time. As an analogy, traditional
known network vulnerability scans take still photographs, while the
invention takes a motion picture;
[0384] Instead of relying on the accuracy of information provided
by the customer point of contact through an interview process, the
invention provides specific and tangible data points for discussion
that facilitates the interview process and educates the customer on
problems in an immediate feedback loop; and
[0385] Because the invention is policy based, and because of the
rigor built into the policy language and analysis engine, the
otherwise manual (and hence error prone) analysis of security
issues relative to the business and architectural context are
enforced with a precise methodology which greatly reduces errors
and omissions during the assessment process.
[0386] It should be appreciated that because the invention operates
passively, the customer network can be monitored while in normal
operation or production.
[0387] Operational Description
[0388] An example of implementing the assessment tool is described
in the following discussion. A consultant arrives at a customer
office with one or more workstations with the monitoring invention
discussed herein loaded. The workstation, or station for short, may
be a laptop computer, or other suitably portable platform. The
monitoring station is attached to the customer network at a
critical network bottleneck, e.g. just inside an Internet firewall,
and monitors all traffic at that point in the network. From a
security point of view, the monitoring station is entirely passive
and invisible to the network. The monitoring station only receives
packets and does not respond to any protocol actions. Due to the
monitoring station's passive nature, no operational impact is
imposed on the subject network. Hence, assessments may be performed
during peak production times, as well as when a network is in a
quiescent state.
[0389] In this example, the monitoring station is left attached to
the network for a long period of time, depending on conditions,
such as, for example, the practical demands of the visit, storage
space on the station, and the amount of traffic on the customer's
network. If appropriate, the station can be left at the customer
site to gather data over a short-term period, such as, for example,
days and weeks.
[0390] In this example of an assessment situation, the policy
specification is used to remove from consideration as much mundane
network traffic as possible, allowing the analyst to concentrate on
more interesting traffic. Due to the opinion of the analyst being
part of the assessment process, there is no fixed goal for the
level of detail needed in the policy specification. In the simplest
case, the analyst generates no policy at all, and examines the
network events one by one (perhaps using the query tool to filter
them). In practice, it can be suggested that the analyst undergoes
a short policy development phase, as the short policy development
phase can serve the analyst well to reduce thousands of network
events into a page or two, which may then be examined by
inspection.
[0391] The invention allows data to be stored in full packet form
for most detailed analysis, or in compressed form storing only
security-sensitive events. The latter form also removes
customer-confidential information, such as, for example, embedded
passwords, so that it is more appropriate for removal from the
customer site. A typical usage scenario is capturing full-packet
data in a short burst, such as, for example, five minutes. After a
brief analysis, a longer data collection is run using the
compressed form.
[0392] The preferred embodiment of the invention provides the
following algorithm for an operator, such as an analyst, to perform
the data analysis on a data packet or on a compressed file of data.
The algorithm is described referring to FIG. 14, as follows:
[0393] 1) Create a null policy, which denies all actions, for a
customer site (copying a file). Set null policy to the current
policy (4002);
[0394] 2) Run the policy engine discussed herein over the input
data and using current policy (4002), and store the resulting data
in a local database (4003);
[0395] 3) Using the query tool discussed herein, examine the
network traffic that is declared in violation by the current policy
(4004);
[0396] 4) Categorize the most frequent traffic based on customer
input:
[0397] a) If the traffic matches known customer-supplied input
patterns, add this traffic to the policy with an OK disposition
(4005);
[0398] b) If the traffic does not match customer-supplied input
patterns, but has high volume, add this traffic to the policy with
an OK,monitor disposition (4006).
[0399] 5) Repeat from step 2 (4009) until only a small, manageable
number of events remains (4007). Then end the algorithm (4008).
[0400] It should be appreciated that the same packet or compressed
file is run by the policy engine multiple times.
[0401] It should be appreciated that in an assessment situation a
policy can be edited by using the policy generator discussed
herein. The invention provides for using the policy generator for
rapid policy development based on transport-level parameters.
Enhanced policy development, using more complex tools, typically is
not necessary in an assessment situation.
[0402] It should also be appreciated implementing the algorithm
discussed above does not take very long. Part or all of the process
may take place at the customer site, in a hotel room, on an
airplane, or back at the analyst's office, for example. When the
process is completed, the analyst has a list of monitored network
events. This list is used as a basis for additional discussion with
the customer to determine the meaning of such events. Experience
has shown that such conversation is useful to the assessment
interviewing process.
[0403] It should also be appreciated that the variations of the
algorithm above can be implemented and are within the scope of the
invention. Examples of variations follow.
EXAMPLE VARIATION I
[0404] An equally preferred embodiment comprises the analysts first
determining the customer requirements and the customer network
credentials. Using this information, the analyst programs an
initial policy. The analyst can derive and use additional
information from the scanning process as described in the algorithm
above.
EXAMPLE VARIATION II
[0405] The customer or analysts designs an initial best policy as a
set of credentials and rules, set all dispositions to DENY, and
monitors the network to determine what the dispositions should
be.
V. Credential/Condition Assertion Verification Optimization
[0406] In the preferred embodiment of the invention, the policy
language describes a policy decision involving two principals, an
initiator and a target principal. These principals are identified
by a set of one or more credentials. For each policy decision the
policy engine ascertains which credential in the policy best
describes the information about the principals involved in an
interaction. Similarly, the policy language herein describes
conditions that in turn describe tests performed on the state of an
associated protocol event.
[0407] The preferred embodiment of the invention provides a
credential/condition assertion verification optimization algorithm
to ensure that the choice of credentials and conditions are made as
efficiently as possible.
[0408] To accomplish credential/condition assertion verification
optimization, the policy engine:
[0409] during the initialization process dynamically creates
comparing functions for principals with credentials, and comparing
functions for state of protocol events with particular conditions
in a high level language such as C++;
[0410] dynamically creates and loads a module containing the
comparing functions;
[0411] during runtime ensures that installed policy file matches
module containing comparing functions, otherwise generates new
module containing comparing functions that correspond to installed
policy file; and
[0412] calls comparing functions as appropriate.
[0413] The preferred embodiment provides a more rigorous algorithm,
an example of which is described in Table O below.
13TABLE O During the initialization process of the policy engine:
the policy engine requests that the parser module load a policy
file, comprising credentials and conditions into an in-memory
representation; the policy engine requests that the parser module
load an assertion verification dynamically loadable library (DLL);
if this DLL exists then it is loaded into memory; and a
predetermined function, for example named dllValidateFunc(),
contained in the loaded DLL is called. If the return value of the
function call is the same as a MD5 hash of the previously loaded
policy file, then loading is complete. Otherwise execution
initialization continues below; because the DLL does not exist or
because the MD5 hash does not match, a code generation function of
the parser module is invoked, which: adds header information to a
C++ assertion code file; adds a function that returns the MD5 hash
of the policy file that was used to generate this C++ file;
iterates through credentials contained in the in-memory represent-
ation, generating C++ function prototype and function declarations
for code that can compare a principal description with the
definition of a credential into the assertion code file, wherein
such comparison is performed by: calling other credential
comparison methods for any credentials used in the definition of
the credential under test; making calls to the policy engine module
to perform comparison operations based on allowable operations for
the built-in types of the policy language; and combining the
results of the above tests with logical operators AND, OR and NOT;
iterates through the conditions contained in the in-memory
represent- ation, generating C++ function prototype and function
declarations for code that can compare a protocol state description
with the definition of a condition into the assertion code file,
wherein such comparison is performed by: calling other condition
comparison methods for any conditions used in the definition of the
condition under test; making calls to the policy engine module to
perform comparison operations based on the allowable operations for
the built-in types of the policy language; and combining the
results of the above tests with logical operators AND, OR and NOT;
compiles and links this generated C++ file to create a dynamically
loadable module containing a compiled version of the
principal/credential and protocol/condition comparison functions;
and loads this newly created module. During the runtime of the
policy engine: each time that it needs to decide whether a
principal is described by a particular credential it computes the
name of the comparison function based on the name of the credential
to be tested; calls the comparison function which returns a Boolean
value that represents whether the credential under test matches the
principal under test; each time that it needs to decide whether a
protocol state satisfies a particular condition it computes the
name of the comparison function based on the name of the condition
to be tested; and calls the comparison function which returns a
Boolean value that represents whether the condition under test
satisfies the protocol state under test.
VI. Network Monitor Internals Descriptions
[0414] The preferred embodiment of the invention provides a network
monitor internals mechanism discussed below that serves to
translate packet data into multiple concurrent streams of network
event data. It accomplishes this by interpreting both sides of each
protocol transaction.
[0415] FIG. 15 shows a high level schematic diagram of the network
monitor 127 accepting packet data from either a live network
interface 125 or a file containing packet data 126. The network
monitor extracts security-sensitive details from the input packet
stream 125, 126, and generates output in a serialized stream of
encoded network event information 115. The preferred encoded format
is DME encoded format, discussed below in section, Network Event
Encoding Format. The output network event information can be stored
for logging or debugging purposes, or can be passed directly to the
policy engine. Thus, the discussed network monitor provides an
efficient process of exporting data from a customer's site, such
process comprising extracting security-sensitive information.
[0416] FIG. 16 shows a schematic diagram of process flow according
to the invention. The network monitor 127 is a single-threaded
program that processes packets (125 or 126) as they are read. Each
packet is passed to a monitor protocol engine 6100 for processing.
When security-sensitive protocol events are encountered in the
packet data, the monitor calls into its output section 6200 to
transmit network or protocol events to the rest of the policy
monitoring system 100 via a network pipe, direct procedure call.
Output section 6200 can also store protocol events in a file for
later processing.
[0417] Protocol Engine
[0418] The preferred embodiment of the invention provides a
protocol engine in the network monitor that can be described with
reference to FIG. 17. FIG. 17 is a block schematic diagram of
features of the protocol engine according to the invention. Input
packet data 115 is read into a known object-oriented structure type
6101, such as, for example, a C structure here named pkt_t
structure. The pkt_t structure 6101 represents a packet on the
network. It provides a stack-based structuring mechanism 6102 that
allows protocol headers and trailers 6103 to be marked in the
packet so that software may focus easily on the correct protocol
layer. The pkt_t structure 6101 also includes generic src 6104 and
dst 6105 address locations, and flags 6106 to pass useful
information up and down a connection stack, for example, if such
packet is transiting from server to client or vice versa.
[0419] The protocol engine 6100 provides one module 6107 for each
protocol implemented 6108. The modules implement a generic series
of operations, a preferred example of such series is provided below
in Table P. A common connection structure 6109 allows connection
data to be arranged in a stack allocation for each access across
layer boundaries. In Java or C++ terminology, for example, each
protocol is a superclass of connection. The layering permits
protocols to assume one or more roles as the layer responsible for
each corresponding boundary, such as, for example: Network,
Transport, Session, Application, or Transactions.
14TABLE P Example of generic operations for each protocol
implementation: 1. init: Call-once initialization 2. Bind(packet,
connection): given the first packet of a connection, attempt to
bind this packet into a new instance of this protocol within
connection. Establish the instance in its proper role(s) within the
connection. 3. Input(packet, connection): given a packet, which has
been associated with a connection (in some cases, connection is
NULL, indicating that no such relationship exists, or exists yet),
process the packet as input to the connection. 4. GiveBack(packet,
connection): given a packet, which has been associated with a
connection at a higher level of protocol, give back the packet to
this layer, so that the data will be received later, as if it was
retransmitted. Typically, packet has been modified to contain only
part of the input data. 5. GetMore(connection, amountNeeded,
fromClientOrServer) returns(packet): given a connection, attempt to
return a packet containing more data on the connection, if such is
available. This call is used from a higher layer of protocol
calling down to a lower layer of protocol. The from ClientOrServer
argument is used to determine if the data is being requested that
was received by the server side or the client side of the
connection. 6. StopCollecting(connection): given a connection,
adjust the protocol stack so that no further data will be processed
on this connection. Depending on the protocol in question, this may
involve discarding data or adjusting filters. A connection which is
not "collecting" attempts to process packets in the most efficient
manner. 7. Shutdown(connection, fromOrg, fromDst): given a
connection, modify the connection state to indicate that the
client, server, or both have acted to take down the connection. The
full generality of the call is needed only for a transport
connection like TCP. 8. Del(connection): given a connection,
arbitrarily delete the instance of this protocol from the
connection object. This call is intended to clean up the resources
used by the connection; Shutdown is used to indicate protocol
agreement that the connection is coming to an end. 9.
Alarm(connection, time): given a connection and the current time,
this call is used to signal an alarm has expired on this
connection. The time argument is the official time of the alarm,
which may not even be related to the current time. 10.
SwitchSrcDst(connection): this call indicates that a higher layer
of software (perhaps a higher level protocol) has determined that
the choice of client and server in this protocol instance are
wrong, and should be reversed. This may happen when initial
connection negotiation packets are not seen by the monitor, but
later information makes the client and server clear.
[0420] It should be appreciated that in the stopCollecting generic
operation, and in a transport protocol, header information in
packets may need to be examined to determine connection state,
allowing freeing of resources when the connection terminates.
Transport protocols discard all subsequent data from the
connection, and do not forward packets on to higher level
protocols. Such mechanism allows the monitor to efficiently process
bulk transfers, encrypted connections, or connections that are no
longer of interest to the policy engine.
[0421] It should be appreciated that the process discussed above
for the stopcollecting generic operation can be appropriate for a
hardware filter to stop packets from arriving.
[0422] The concept of the current time in the monitor flows from
the packet level upwards. That is, time is associated with the
packet and is maintained throughout the packet. When the network
monitor is running in real time off live packet data, current time
reduces to the time a packet was received, which may be earlier
than the time when the packet is processed. When the network
monitor is running off stored packet data, current time in the
monitor has no relation to actual current time. The packet is
processed relative to the time it was received and whereby time
intervals remain the same. Also, results can be lined up in the
database reflecting the point of reference of the time the packet
was received.
[0423] The network monitor provides support for setting alarms on
connections. An alarm is set by registering a connection to receive
a signal when the network monitor transitions to a predetermined
value of current time. The signal consists of a call to a generic
alarm operation in every protocol layer registered with such
connection. Alarm handlers are called in order from lowest protocol
layer to highest protocol layer.
[0424] Because network monitor functionality is based on network
events that can map to network connections, the network monitor
provides a connectionless association feature. By using the
feature, the network monitor registers the fact that it noticed two
IP hosts communicating. Typically, an association is long lived,
whether or not the network monitor knows its intention. Examples of
associations are a series of ICMP PING/PING REPLY packets and a
stream of IPSEC packets. The network monitor treats associations as
connections. Indeed, often associations are connections at a higher
level of protocol.
[0425] Output Section
[0426] The preferred embodiment of the invention provides an output
section in the protocol engine. FIG. 18 is a high level flow
diagram of the preferred output section according to the invention.
The output section 6200 of the network monitor receives network
event data from the protocol engine and generates outbound calls
6203 to transmit such data to the policy engine or to a file.
[0427] The output section 6200 works by allowing the network
monitor to establish a transaction which forms an association
between a monitor connection and a network event in the policy
engine. FIG. 19 shows a schematic diagram of a transaction 6204,
comprising an association 6205 between a subject monitor connection
6206 and a network event 6207. Typically, the lifetime of the
connection 6206, the transaction 6204, and the network event 6207
is similar.
[0428] The output section's interface comprises a set of calls to
establish communication with the policy engine, and to start and
finish transactions, and a set of protocol-specific calls. The
calls progress as follows:
[0429] Connect
[0430] BeginTransaction
[0431] ProtocolEvent1
[0432] ProtocolEvent2
[0433] . . .
[0434] EndTransaction
[0435] Disconnect
[0436] It should be appreciated that in addition to the calls
above, multiple transactions can be active at a time, as long as
each transaction follows the ordering described above.
[0437] The output section internally translates such calls into a
generic set of calls, an example of which is listed below. At
initialization of the network monitor, the output section is
configured with a chain of output generic modules, each of which is
used as filter on the output data. An example of the implemented
modules follows:
[0438] NULL: acts as an endpoint, but discards input data without
doing anything;
[0439] SM: connects by procedure call directly to policy
processing;
[0440] ENC: generate encoded form of output; and
[0441] LOG: generate textual form of output.
[0442] In an equally preferred embodiment of the invention, the
network monitor also includes an input section that decodes an
encoded version of events. For an example application, in a
real-time monitoring system embodiment the monitor 127 processes
network traffic 125 in real time and uses ENC to generate encoded
output. The encoded output is transmitted in real-time over a TCP
connection where it is decoded and connected using SM to the Policy
Engine 102.
[0443] In another embodiment of the invention, the output section
is used for testing purposes. The output section is configured
using command line arguments. An example of a n algorithm for such
testing follows:
[0444] 1. Capture packet data into a file;
[0445] 2. Run the network monitor on the packet data, using
LOG.fwdarw.ENC. Store the logged textual data and the encoded form
into separate files;
[0446] 3. Run the network monitor on the encoded data, using
LOG.fwdarw.NULL. Store the logged textual data in a file.
[0447] 4. Compare the two textual files to make sure that the
decoded version matches the logged textual file.
[0448] Network Event Encoding Format
[0449] The preferred embodiment of the invention provides a
technique for network event encoding to be used by the network
monitor. The encoding technique is designed for both archival and
transmission purposes. The basic format of the encoding is:
[0450] Header
[0451] Embedded agent descriptors
[0452] Type map
[0453] Encoded transactions
[0454] An example of the preferred form of the header follows:
[0455] 4 byte magic number: "SMKo"
[0456] 1 byte major version=2
[0457] 1 byte minor version=1
[0458] 4 bytes containing the size of this header
[0459] 8 bytes (struct timeval) begin time, which is a time which
is less than or equal to every timestamp in this encoded record
[0460] 4 bytes offset of agent descriptor section
[0461] 4 bytes indicating number of agent descriptors
[0462] 4 bytes offset of type map section
[0463] 4 bytes indicating number of type map entries
[0464] 4 bytes offset to first transaction record
[0465] 4 bytes size of this file, or 0xFFFFFFFF if unknown.
[0466] 4 bytes 1's complement checksum of this file or 0xFFFFFFFF
if unknown
[0467] The agent descriptor section is used to store a possibly
null list of agent descriptors that are configured into the network
monitor at encoding time. The agent descriptors are strings that
plug into a particular policy language policy. They indicate the
location of the subject monitor in the subject network wiring
structure, enabling rules that apply to such location in the
network and disable rules that do not apply.
[0468] A preferred agent descriptor section comprises an array,
where each element of the array is an ASCII string, preceded by a
single byte giving its length.
[0469] The size of the array is given in the header cited above.
The preferred type map section is used to improve maintainability
of the full policy monitoring system. Provided by the type map
section is a mapping between update types used in an encoded record
and the update types' string names. The decoding module uses this
information to detect new update types that are not supported by
mapping known updates to the correct values. That is, because new
update types typically are not interpretable by old software, they
are therefore successfully skipped.
[0470] A preferred type map section comprises an array, where each
element of the array contains a 4-byte type value, a single byte of
string length, and the ASCII name of the type. The size of the
array is given in the header cited above.
[0471] The preferred encoded transactions comprise an array of
individual update encodings. The size of the array is either
derivable from the header file size information, or is unbounded,
such as, for real-time monitoring.
[0472] A preferred header for an individual update has the
following format:
[0473] 1 byte, giving the update type
[0474] 4 bytes, giving the size of this header in bytes, not
including the length of the header
[0475] 8 bytes (struct timeval) giving the absolute time when this
update occurred
[0476] 4 bytes, giving the packet number of this update since the
monitor started (first packet=packet #0)
[0477] 4 bytes, giving the eventlD of this update, which is the
number of BEGIN_TRANS updates that occurred before this one, since
the monitor started
[0478] Following the header a body contains additional
update-type-specific data, or possibly none.
[0479] To understand all events that transpire on a connection, it
is necessary to combine events of different protocol layers. For
example, an update, named SM_IP_ASSOCIATION, provides IP src and
dst addresses and establishes a peer relationship. Subsequent
events assume that this information is known and builds on it. For
example, an update named ICMP_ECHO has no body at all.
[0480] An example of a set of update types and corresponding
encoding body for each update, according to the invention is given
below in Table Q. The meaning of the term "string" is: if
length(string) is <255, then byte[length], byte[string][length],
else byte[0xff], byte[a], byte[b], byte[c], byte[d],
byte[string][length] where a,b,c,d are the four (big-endian) bytes
of length.
15TABLE Q SM_BEGIN_TRANS Body: none Meaning: begin new transaction
(network event) SM_END_TRANS Body: none Meaning: end previously
"begin" transaction (network event) SM_PUOSU Body: none Meaning:
the monitor can glean no more useful information about this network
event. The policy engine should process policy and give additional
input to the monitor. SM_DEBUG_MSG Body: string Meaning: debug
message, to be inserted into SPM debugging log. SM_PROTOCOL_UNKNOWN
Body: none Meaning: the monitor is unable to determine the higher
level protocol SM_FTP_DATAOPEN Body: none Meaning: This (new)
connection is an FTP data connection SM_FTP_DATACLOSE Body: none
Meaning: This FTP data connection has closed normally.
SM_FTP_DATAABORT Body: none Meaning: This FTP data connection has
close abnormally. SM_FTP_OPEN Body: none Meaning: This (new)
connection is an FTP control connection SM_FTP_CLOSE Body: none
Meaning: This FTP control connection has closed normally.
SM_FTP_ABORT Body: none Meaning: This FTP control connection has
closed abnormally SM_FTP_NOAUTH Body: 4-byte, number of
authentication failures Meaning: This FTP control connection has
failed to authenticate SM_FTP_AUTH Body: String, user name String,
password, if user was anonymous 4-byte, password length 1-byte,
nonzero if password contains alphabetics 1-byte, nonzero if
password contains numeric characters 1-byte, nonzero if password
contains characters which are non- alphanumeric 4-byte, number of
authentication failures Meaning: This FTP control connection has
successfully authenticated SM_FTP FILEGET SM_FTP FILEPUT SM_FTP_DEL
SM_FTP MKDIR SM_FTP RMDIR Body: String, file name 1-byte, FTP error
code String, FTP error message Meaning: attempt to perform FTP
RETR, STORE, DEL, MKD, RMD command. If immediate failure, the error
is given in the message. For GET/PUT, if transfer is proceeding,
error status comes in the XFERDONE message. SM_FTP_XFERDONE Body:
String, unused 1-byte, FTP error code String, FTP error message
Meaning: status from continuing FILEPUT or FILEGET command SM_FTP
RENAME Body: String, from file name String, from file name 1-byte,
FTP error code String, FTP error message Meaning: attempt to
perform FTP file rename command. If failure, the error is given in
the message. SM_HTTP_CLOSE Body: none Meaning: This HTTP connection
has closed normally. SM_HTTP_METHOD Body: 1-byte, method code (one
value for each HTTP method) 1-byte, HTTP version (major) 1-byte,
HTTP version (minor) String, URL Meaning: Describes HTTP method
line SM_HTTP_POSTDATA Body: 1-byte, always true. 1-byte, nonzero if
this is the last POSTDATA call to complete all the post data.
String, post data Meaning: contains some or all of the post data
for an HTTP POST method. SM_HTTP_REQCTYPE SM_HTTP_RESPCTYPE Body:
String, content type Meaning: HTTP content type from request or
response header. SM_HTTP_REQCOOKIE SM_HTTP_RESPSETGOOKIE Body:
String Meaning: HTTP cooking/set-cookie headers SM_HTTP_REQHEADER
SM_HTTP_RESPHEADER Body: 1-byte, nonzero if this is the last group
of header info 4-byte, number of header lines String[number of
header lines] Meaning: contains HTTP header information from
request or response header. SM_HTTP_REQHEADEREND
SM_HTTP_RESPHEADEREND Body: none Meaning: End of request or
response header has been reached. SM_HTTP_RESPONSE Body: 4-byte,
response code 1-byte, HTTP version (major) 1-byte, HTTP version
(minor) String, response message Meaning: encoding of the HTTP
response header line SM_HTTP_MISS Body: none Meaning: Monitor was
unable to parse the HTTP transaction (perhaps because of missed
packets) SM_ICMP_BADCODE Body: none Meaning: ICMP packet received
of unknown type SM_ICMP_DU_FRAG (destination unreachable:
fragmentation needed and DF set) SM_ICMP_DU_HOST (destination
unreachable: host unreachable) SM_ICMP_DU_NET (destination
unreachable: net unreachable) SM_ICMP_DU_PORT (destination
unreachable: port unreachable) SM_ICMP_DU_PROT (destination
unreachable: protocol unreachable) SM_ICMP_DU_SRCRT (destination
unreachable: source route failed) SM_ICMP_DU_FILTER (destination
unreachable: packet filtered) SM_ICMP_PARAM (parameter problem)
SM_ICMP_SRCQ (source quench) SM_ICMP_TE_EXCD (time to live exceeded
in transit) SM_ICMP_TE_FRAG (fragment reassembly time exceeded)
Body: 4-byte, IP src address 2-byte, UDP/TCP src port 4-byte, IP
dst address 2-byte, UDP,TCP src port 4-byte, IP protocol Meaning:
This connection contains a particular ICMP error. The body gives
information from the nested packet within the ICMP packet.
SM_ICMP_ECHO SM_ICMP_ECHOR Body: none Meaning: ICMP echo / echo
reply seen (echo is commonly called "ping"). SM_ICMP_IREQ
SM_ICMP_REQR Body: none Meaning: ICMP information request/reply
seen SM_ICMP_RD_HOST (Redirect datagrams for the Host)
SM_ICMP_RD_HOSTTOS (Redirect datagrams for the Type of Service and
Host) SM_ICMP_RD_NET (Redirect datagrams for the Network)
SM_ICMP_RD_NETTOS (Redirect datagrams for the Type of Service and
Network) Body: 4-byte, gateway address 4-byte, IP src address
2-byte, UDP/TCP src port 4-byte, IF dst address 2-byte, UDP/TCP src
port 4-byte, IP protocol Meaning: For the given ICMP redirect, the
body gives gateway information and information from the nested
packet within the ICMP packet. SM_ICMP_TSTMP SM_ICMP_TSTMPR Body:
none Meaning: ICMP Timestamp / Timestamp reply seen
SM_ICMP_ASSOCIATION Body: none Meaning: This connection contains an
ICMP-level association. SM_IPINFO_IP_ASSOCIATION Body: 6-byte, src
MAC address 6-byte, dst MAC address 4-byte, IF src address 2-byte,
UDP,TCP src port 4-byte, IP dst address 2-byte, UDP/TCP src port
1-byte, IP protocol 1-byte, IP version Meaning: an IP protocol
association exists on this connection. SM_TCP_CONNECT
SM_TCP_MISSED_CONNECT Body: none Meaning: a (new) TOP connection
exists on this connection. In the case of a "missed" connect, the
first packets from the connection were not seen, so the monitor is
unable to properly classify the connection. SM_TCP_DATA Body: none
Meaning: data has transited this connection SM_UDP_ASSOCIATION
Body: none Meaning: This connection contains a (new) UDP
association SM_SSH_AUTH Body: 4-byte, client version (major)
4-byte, client version (minor) 4-byte, server version (major)
4-byte, server version (minor) 4-byte, authmask, gives which cipher
suites are supported (see SSH specification) 4-byte, cipher suite
selected Meaning: a successful SSH authentication has occurred.
SM_SSH_ABORT SM_SSH_CLOSE Body: none Meaning: the SSH connection
has terminated. An ABORT means that the transport layer aborted.
SM_SSH_HANDSHAKE_FAILURE Body: none Meaning: the monitor was able
to determine that the SSH handshake failed. SM_SSH_HANDSHAKE_MISS,
// We cannot interpret the handshake. Body: none Meaning: the
monitor was unable to determine whether the SSH handshake failed or
succeeded. SM_SSL_ABORT (fatal alert) SM_SSL_WARNING (non-fatal
alert) SM_SSL_HANDSHAKE_FAILURE (alert seen, indicates handshake
failure) Body: 1-byte, alert level (see SSL3 specification) 1-byte,
alert description Meaning: The SSL connection has signaled an
ALERT. SM_SSL_HANDSHAKE_SUCCEED Body: none Meaning: the SSL
connection has completed its handshake SM_SSL_HANDSHAKE_ABORT Body:
none Meaning: the SSL connection was aborted by transport level
without handshake completion SM_SSL_HANDSHAKE_MISS Body: none
Meaning: The monitor was unable to determine the SSL session
credentials. Because of resumed sessions, this may mean that the
session was completely successful. SM_SSL_SERVER_HELLO Body:
1-byte, version (major) 1-byte, version (minor) 4-byte, ciphersuite
(enum) 1-byte, non-zero if a resumed session String, sessionid
Meaning: SSL (client+)server hello information SM_SSL_CLIENT_CERT
SM_SSL_SERVER_CERT Body: String, client or server certificate chain
Meaning: client or server certificate SM_TCP_ABORT Body: none
Meaning: TCP RST packet received, killed connection SM_TCP_CLOSE
Body: none Meaning: TCP normal close (both sides) SM_TCP_TIMEOUT
Body: none Meaning: TCP death timer expires, killing
connection.
[0481]
16TABLE S Evaluation Algorithm In the preferred embodiment the
policy engine applies a poilcy evaluation algorithm to each
incoming protocol event. The algorithm results in a selection of a
policy rule applicable to the protocol event and may produce an
immediate or final disposition. Following is a step-by-step
description of the evaluation algorithm according to the preferred
embodiment. It is noted that the evaluation procedure described
herein below is in conceptual form and does not take into account
any possible runtime optimizations: 1) Select a set of rules
applicable to an Agent reporting an event; 2) From said set, select
a second set of rules applicable to an associated examined
protocol. 3) From said second set, select a third set of rules
applicable to an associated examined protocol action. 4) Starting
with a most specific policy rule in said third set and descending
to a least specific rule find a policy rule satisfied by said
protocol event. A matching algorithm according to the preferred
embodiment is as follows: a) If one or more orderly listed
prerequisite rules are specified, ensure at least one of said
prerequisite rules is satisfied by a previously processed protocol
event. In the preferred embodiment a prerequisite rule is satisfied
if it is a pending policy rule for the protocol event. b) Match
initiator and target credentials in the policy rule against the
corresponding initiator and target credentials presented in the
protocol event. 5) If a policy rule satisfying the protocol event
is not found the policy engine generates a disposition for the
network event indicating that a policy specification error was
encountered. Effectively the processing of the network event
thereby terminates. 6) If a policy rule satisfying the protocol
event is found, the policy engine checks for other rules having a
same ranking number and also satisfying the event. If such rules
are found the policy engine uses the following algorithm in the
preferred embodiment to select a single applicable rule: a) Rules
that specify all protocols (i.e. using ignore or present) are less
specific than rules that explicitly list a set of one or more
protocols. b) Rules that specify all actions (i.e. using ignore or
present) are less specific than rules that explicitly list a set of
one or more actions. c) Rules that have prerequisites are more
specific than rules that do not have prerequisites. Rules that
specify a higher-ranking prerequisite are more specific than rules
that specify a lower-ranking prerequisite. In the preferred
embodiment a ranking relationship is relevant only if both
prerequisite rules belong to a same protocol-action group. d) If
thereafter a single rule is determined as more specific than the
others it is selected for the protocol event. If more than one rule
remains the policy engine sorts the remaining rules in increasing
lexical order by name and selects a first rule from the sorted
rules having an immediate disposition indicating in decreasing
order of precedence: i) a policy violation (any disposition code
other than OK or CONTINUE); ii) CONTINUE (allows other rules to
examine further the network event); and iii) OK The outcome of the
policy evaluation algorithm herein above is a policy rule that
satisfies the protocol event. If an immediate outcome is specified
for that rule, it is executed, producing a disposition for the
protocol event. If the disposition comprises a final disposition
code (any code other than CONTINUE), the disposition is also the
final disposition for the network event. Otherwise in the preferred
embodiment the selected policy rule is a pending policy rule for
the network event. In absence of any further protocol events the
pending policy rule is promoted to selected policy rule. A final
outcome of the selected policy rule is executed producing a final
disposition for the network event.
VII. An Exemplary User Interface for Providing and Reporting
Processed and Analyzed Network Data to an End User
[0482] An exemplary user interface for providing and reporting the
processed and analyzed network data from the database (FIG. 1a 165)
to an end user is provided below.
[0483] It should be appreciated that examples of a typical end user
using such interface are, but are not limited to a customer whose
network is being monitored, an operations analyst reviewing the
customer's network environment and network data, and/or a policy
analyst reviewing the network data and its conformance to network
policy.
[0484] The preferred embodiment of the invention uses a web page
paradigm as an example of a type of user interface, and is
described with reference to figures of screen prints of web pages
herein. While the claimed invention herein has disclosed a web page
implementation of a user interface, it will be appreciated by those
skilled in the art that such user interface readily encompasses any
form, that can be substituted therefore to effect a similar result
as is achieved by the web page, including but not limited to any
graphical user interface or non-graphical user interface.
[0485] The preferred embodiment of the invention is described with
reference to FIG. 20 and comprises a system dashboard, label 20000
on a home page, wherein the dashboard 20000 is kept up to date with
current monitoring information from the monitored network.
[0486] In the preferred embodiment of the invention, the dashboard
20000 updates once every five minutes. It should be appreciated
that different update rates can be used to keep the data on the
dashboard 20000 current, and that parts of the underlying customer
data may be updated at a different, such as a slower rate.
[0487] The preferred embodiment of the invention provides a tear
off feature on the system dashboard 20000. In this example, the end
user clicks on a tear off tab 20010 to open a tear off console
window. FIG. 21 shows an example of a tear off console window
according to the invention. It is intended that the end user keep
the console window open on the computer desktop all day long to
view high level reporting of the health of the monitored
network.
[0488] The preferred embodiment of the invention provides an
outstanding alerts area 20020 of the dashboard and consists of a
FIFO queue of CRITICAL alerts that have been generated by the
policy monitoring system (FIG. 1a 106). In the preferred embodiment
of the invention the following applies. The size of the alert list
can be limited to a predetermined number of elements. The total
number of open alerts can be displayed within the alerts area
20030.
[0489] The underlying data is updated on a real-time basis. Entries
in the list link to alert details, as depicted in FIG. 28. In this
example, clicking on an entry in the list 20030 opens up an alert
details page 2801 for that particular alert, comprising such alert
details as, for example rule, disposition, time of alert, type of
alert, source ip-address, destination ip-address, and the like.
[0490] The preferred embodiment of the invention provides a health
monitor 20040 to show a visual representation of the severity
categories into which the current observed traffic has been
assigned over a predetermined amount of time. In this example, the
underlying data is updated every five minutes and summarizes
traffic over the last one hour and last twenty four hour periods.
CRITICAL and HIGH severity alerts have a red bar 20050, MEDIUM,
WARNING and MONITOR will use a yellow bar 20060, and all others
will be green 20070.
[0491] The preferred embodiment of the invention provides access to
current summary reports. An example is shown in FIG. 20 as part of
the end user's home page. Such screen allows the end user to
generate queries that summarize report data filtered by the
monitoring point and over configurable time periods. An interface
feature, such as a dropdown listbox 20090 allows the end user to
choose one of a predetermined set of time periods, such as but not
limited to the following:
[0492] Select date range--A specific time period expressed in
starting month, day and hour, followed by ending month, day and
hour using an interface feature such as dropdown listboxes
20091;
[0493] Last two hours;
[0494] Last 24 hours;
[0495] Today (since midnight);
[0496] Yesterday (00:00-23:59:59);
[0497] Last seven days;
[0498] This month (from first to present);
[0499] Last month (from first to end of month);
[0500] Last three months (three months back from present); and
[0501] Custom (retrieves date/time range from the last manually
configured query).
[0502] The preferred embodiment of the invention provides an events
summary view as shown in FIG. 22.
[0503] In the example shown in FIG. 22, viewing the summary for a
specific time a table 2202 displaying the following information,
when the conformance tab 2203, the violators tab 2204, or the
targets tab 2205, respectively, is selected:
[0504] A conformance chart/table shown in FIG. 22, displaying the
count of violations for each rule/disposition pair.
[0505] An icon 2206 links to a network event details page, such as
shown in FIG. 23 that contains details of events that make up this
count, i.e. all network events with such rule/disposition pair that
occurred in the given time period.
[0506] A violators chart 2901 and table 2902 shown in FIG. 29,
displaying the count 2903 of the number of violations for each of
the top violating ip-addresses 2904.
[0507] An icon 2206 links to a network event details page, such as
shown in FIG. 23 that contains details of events that make up this
count, i.e. all network events with such originating ip-address
that occurred in the given time period.
[0508] A targets chart 3001 and table 3002 shown in FIG. 30,
displaying the count 3003 of the number of violations for each of
the top destination ip-addresses 3004.
[0509] An icon 2206 links to the a event details page, such as
shown in FIG. 23 that contains details of events that make up this
count, i.e. all network events with such destination ip-address and
port that occurred in the given time period.
[0510] FIG. 22 shows the events summary report for conformance.
[0511] The preferred embodiment of the invention provides a link to
network events detail information. In this example, a separate link
2206 builds a network events details page as shown in FIG. 23. FIG.
23 contains a table that may be sorted or reverse sorted by any of
the columns displayed 2301 of all violating network events with
such a rule/disposition pair that occurred in the chosen time
period.
[0512] In the preferred embodiment of the invention, the summary
page (FIG. 22) contains a specification of the date range of the
data being displayed. In particular, if the start of the range
falls outside the range of date for acquiring user data then the
actual start date of the user data is displayed.
[0513] It should be appreciated that in another equally preferred
embodiment, user defined and configurable query and reports
settings can be stored, for example, in a user's preferences or
profile.
[0514] The preferred embodiment of the invention comprises trend
reports on the dashboard, wherein such reports comprise charts that
link to a network events summary page containing details of the
summarized traffic. More specifically, the charts, unless otherwise
explicitly specified, are bar charts, each of which link to the
network events summary page.
[0515] Referring to FIG. 20, the preferred embodiment of the
invention comprises a section, such as a QuickWeek section 20100 of
the end user's main page, such as a login page or home page that
contains trend graphs, such as but not limited to the
following:
[0516] During the past seven days, the five most frequent
rule/disposition combinations versus count 20110;
[0517] During the past seven days, the five most frequent violator
ip-addresses versus count 20120; and
[0518] During the past seven days, the five most frequent target
ip-addresses versus count 20130.
[0519] It should be appreciated that another equally preferred
embodiment of the invention comprises an input means for the end
user to customize which trends appear in the trend, e.g. QuickWeek
section, and to customize the time period being viewed.
[0520] The preferred embodiment of the invention comprises trend
charts that are embedded into details pages. Each of the trend
charts allows the end user to dynamically configure a time range by
a means such as a pulldown menu.
[0521] Examples of such embedded trend charts are:
[0522] Policy effectiveness;
[0523] Number of policy changes over time;
[0524] Event Summary (such as for the following):
[0525] Conformance: Graphical view of the data for the specified
time period 2201;
[0526] Violators: Graphical view of the data for the specified time
period; and
[0527] Targets: Graphical view of the data for the specified time
period; and
[0528] Network Event Details (such as for the following):
[0529] Conformance Event Details (FIG. 23):Violator count over time
for a particular rule/disposition combination 2303;
[0530] Violators Event Details: Conformance count over time for a
particular violator; and
[0531] Target Event Details: Conformance count over time for a
particular target;
[0532] All, e.g. in chronological order:Conformance count over time
for a particular time period.
[0533] The preferred embodiment of the invention provides event
detail reports, such as for but not limited to network event
details, protocol event details, and alert details, described
below.
[0534] The preferred embodiment of the invention provides a network
event details page containing listed fields in columns that vary
according to the violation type, such as, for example, All,
Conformance (FIG. 23), Violator, and Target that had been selected
at the summary level. For each type, except All, rather than repeat
the field or column(s) which reiterate the violation, it will be
displayed in the heading of the events detail page. For example,
after choosing to view event details for a particular target, the
DstIP will not be repeated in every row. Each of the columns may be
used to sort or reverse sort the report by clicking on that
column's heading name. Following is a list of types of data
provided in a network event details page:
[0535] Monitoring Point;
[0536] Disposition Name;
[0537] Rule Name;
[0538] Disposition Code;
[0539] Severity;
[0540] Src IP;
[0541] Src Port;
[0542] Dst IP;
[0543] Dst Port;
[0544] IPProtocol;
[0545] Event Time: event times can be stored throughout the system
in UTC; and
[0546] Application Data:
[0547] ICMP-ICMP action code;
[0548] HTTP-URL;
[0549] FTP-Filename;
[0550] SSL-Ciphersuite, Issuer and Subject's certificate
CommonName, Certificate Status;
[0551] SSH-Authentication handshake status; and
[0552] Application Status Code
[0553] HTTP-StatusCode.
[0554] The preferred embodiment of the invention provides a
protocol event details page as depicted in FIG. 24 and that is
created in the context of a particular network event instance. This
data is retrieved on an as-needed basis from a database. The
content of this page reflects the data available in a protocol
event view of the QueryTool and is specific to the protocol or
protocols being displayed. Such data includes, but is not limited
to:
[0555] Data from such attributes as IP address, interface address,
protocol ID, service port, URL, file pathname, user name, password
metrics, public key certificate, encrypted session parameters and
status codes;
[0556] Protocol-specific actions such as HTTP methods, TCP protocol
messages, ICMP message codes, FTP control commands, and
authentication steps.
[0557] The preferred embodiment of the invention provides an alert
event details page as depicted in FIG. 28 containing, but not
limited to the following:
[0558] details of the network event that caused the alert;
[0559] rule and disposition name that triggered alert;
[0560] log comment from the disposition;
[0561] time at which the alert was generated;
[0562] initiator ip address of the corresponding non-conformant
traffic;
[0563] target ip address of the corresponding non-conformant
traffic;
[0564] an icon that links to the network event details page
describing the non-conformant network event; and
[0565] checkbox to clear the alert.
[0566] The preferred embodiment of the invention provides a policy
update page containing, but not limited to a table displaying each
time a new policy is installed on the security policy management
system discussed herein. This table contains, but is not limited
to:
[0567] Date of the policy installation;
[0568] Description of policy; and
[0569] A link to the English description that represents the newly
installed policy.
[0570] It should be appreciated that in the preferred embodiment of
the invention alerts are generated whenever a disposition with a
CRITICAL severity is assigned to a network event, each alert
generating an email containing, but not limited to the following
information:
[0571] time the alert occurred;
[0572] rule and disposition name that triggered alert;
[0573] log description, if any, from the corresponding
disposition;
[0574] initiator ip address of the corresponding non-conformant
traffic;
[0575] target ip address of the corresponding non-conformant
traffic; and
[0576] link to the network event detail describing the
non-conformant network event.
[0577] The preferred embodiment of the invention provides a
customer page that allows the user to configure a list of email
addresses within a customer's organization that shall receive alert
email.
[0578] Another equally preferred embodiment provides means for
accessing ad-hoc queries for the end user, such as, but not limited
to, filtering results by any one or all of the following:
[0579] Protocol of the rule name;
[0580] Policy rule name;
[0581] A regular expression within the rule name;
[0582] Disposition name of the violation;
[0583] A regular expression within the disposition name;
[0584] Source ip-address;
[0585] A regular expression with source ip-address;
[0586] Target (Destination) ip-address;
[0587] A regular expression within target (destination)
ip-address;
[0588] Target (destination) port; and
[0589] A regular expression within target (destination) port.
[0590] An example of a means for accessing ad-hoc queries is an
advanced search feature, such as for example, an advanced search
dialog box 3100, as depicted in FIG. 31. In the preferred
embodiment of the invention, the advanced search dialog box 3100
comprises list boxes for such categories, such as protocol 3101,
rule 3102, and disposition 3103, and text boxes for descriptions,
such as regular expression in a rule 3104 or disposition 3105 and
ip-addresses 3106.
[0591] In the preferred embodiment of the invention, an end user
can open the advanced search dialog box 3100 from an Advanced
Search link 3201 on the dashboard, as depicted in FIG. 32, or from
any event summary or event details page.
[0592] The preferred embodiment of the invention provides
informational aids. For example, the following information about a
user's policy is available via a variety of features, such as but
not limited to links, tool tips, and the like:
[0593] Customer specific policy interpretation, such as provided by
English language representation;
[0594] Rule and disposition descriptions as defined by the user in
the user's policy, resolved DNS names for ip-addresses, and TCP and
UDP service names; and
[0595] A copyright page containing copyrights and trademarks as
required by licensing agreements with vendors.
[0596] The preferred embodiment provides links to descriptions of
rules, dispositions, ip-addresses, and the like, displayed, for
example in a pop up window whenever the user's cursor is over the
respective field, as depicted in FIG. 22 2207, FIG. 23 2302, FIG.
25 2501, FIG. 26 2601, and FIG. 27 2701, respectively.
[0597] The preferred embodiment of the invention provides links on
each page that include, but are not limited to:
[0598] Context sensitive help per-page.
[0599] In the preferred embodiment of the invention, each details
page contains a button linking to a printer friendly version of the
page.
[0600] In the preferred embodiment of the invention, regardless of
the time zone the user's or the policy monitoring systems runs on,
such as, for example Universal Time Coordinates (UTC). Any time
being displayed to the user, such as, for example, on a website or
in contents of emails, is converted to the user's time zone and as
such is explicitly displayed.
[0601] Although the invention has been described in detail with
reference to particular preferred embodiments, persons possessing
ordinary skill in the art to which this invention pertains will
appreciate that various modifications and enhancements may be made
without departing from the spirit and scope of the claims that
follow.
* * * * *