U.S. patent application number 15/466695 was filed with the patent office on 2017-09-07 for logical / physical address state lifecycle management.
The applicant listed for this patent is TRUSTWAVE HOLDINGS INC.. Invention is credited to Michael J. McDaniels, Ronald J. Miller, Mark L. Wilkinson.
Application Number | 20170257339 15/466695 |
Document ID | / |
Family ID | 40434218 |
Filed Date | 2017-09-07 |
United States Patent
Application |
20170257339 |
Kind Code |
A1 |
Wilkinson; Mark L. ; et
al. |
September 7, 2017 |
LOGICAL / PHYSICAL ADDRESS STATE LIFECYCLE MANAGEMENT
Abstract
Methods, apparatus, and articles of manufacture for managing
logical and physical address state lifecycles are disclosed. An
example apparatus includes a network interface to capture a first
data packet from a first network, and a data transmitter to
transmit the first data packet from the apparatus to a security
device, where the security device is to determine whether the first
data packet is associated with a threat. The apparatus further
includes a table updater to adjust an address resolution protocol
(ARP) table of the apparatus to mask a device communicatively
coupled to the apparatus from the threat when the apparatus obtains
a second data packet, where the second data packet is generated in
response to the security device determining that the first data
packet is associated with the threat.
Inventors: |
Wilkinson; Mark L.; (Austin,
TX) ; Miller; Ronald J.; (Kyle, TX) ;
McDaniels; Michael J.; (Hutto, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TRUSTWAVE HOLDINGS INC. |
Chicago |
IL |
US |
|
|
Family ID: |
40434218 |
Appl. No.: |
15/466695 |
Filed: |
March 22, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13603388 |
Sep 4, 2012 |
9667589 |
|
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15466695 |
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|
10676505 |
Oct 1, 2003 |
8260961 |
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13603388 |
|
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60415290 |
Oct 1, 2002 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 61/10 20130101;
H04L 63/1433 20130101; H04L 29/12028 20130101; H04L 61/103
20130101 |
International
Class: |
H04L 12/46 20060101
H04L012/46 |
Claims
1. An apparatus comprising: a network interface to capture a first
data packet from a first network; a data transmitter to transmit
the first data packet from the apparatus to a security device, the
security device to determine whether the first data packet is
associated with a threat; and a table updater to adjust an address
resolution protocol (ARP) table of the apparatus to mask a device
communicatively coupled to the apparatus from the threat when the
apparatus obtains a second data packet, the second data packet
generated in response to the security device determining that the
first data packet is associated with the threat.
2. The apparatus of claim 1, wherein the first data packet is at
least one of an address resolution protocol (ARP) packet, an
Internet control message protocol (ICMP) packet, or a TCP
packet.
3. The apparatus of claim 1, wherein determining whether the first
data packet is associated with the threat includes determining
whether the first data packet violates a behavioral rule or a
reconnaissance rule.
4. The apparatus of claim 1, further including determining whether
a source Internet Protocol (IP) address of the first data packet is
on a second network, the second network including the security
device and the device.
5. The apparatus of claim 4, wherein the second data packet is an
ARP packet, wherein a source of the ARP packet includes an IP
address of the device and a synthetic media access control (MAC)
address, wherein the synthetic MAC address is not in use on the
second network.
6. The apparatus of claim 5, wherein a destination of the ARP
packet includes an IP address of the router and a MAC address of
the router.
7. A method comprising: capturing, at a router, a first data packet
from a first network; transmitting the first data packet from the
router to a security device, the security device to determine
whether the first data packet is associated with a threat; and in
response to the security device determining that the first data
packet is associated with the threat, obtaining, at the router, a
second data packet to adjust an address resolution protocol (ARP)
table of the router to mask a device communicatively coupled to the
router from the threat.
8. The method of claim 7, wherein the first data packet is at least
one of an address resolution protocol (ARP) packet, an Internet
control message protocol (ICMP) packet, or a TCP packet.
9. The method of claim 7, wherein the security device and the
device are communicatively coupled to the first network via the
router.
10. The method of claim 7, wherein determining whether the first
data packet is associated with the threat includes determining
whether the first data packet violates a behavioral rule or a
reconnaissance rule.
11. The method of claim 7, further including determining whether a
source Internet Protocol (IP) address of the first data packet is
on a second network, the second network including the security
device and the device.
12. The method of claim 11, wherein the second data packet is an
ARP packet, wherein a source of the ARP packet includes an IP
address of the device and a synthetic media access control (MAC)
address, wherein the synthetic MAC address is not in use on the
second network.
13. The method of claim 12, wherein a destination of the ARP packet
includes an IP address of the router and a MAC address of the
router.
14. A storage device or storage disc comprising instructions that,
when executed, cause a machine to at least: capture, at a router, a
first data packet from a first network; transmit the first data
packet from the router to a security device, the security device to
determine whether the first data packet is associated with a
threat; and obtain, at the router, a second data packet to adjust
an address resolution protocol (ARP) table of the router to mask a
device communicatively coupled to the router from the threat when
the security device determines that the first data packet is
associated with the threat.
15. The storage device or storage disc of claim 14, wherein the
first data packet is at least one of an address resolution protocol
(ARP) packet, an Internet control message protocol (ICMP) packet,
or a TCP packet.
16. The storage device or storage disc of claim 14, wherein the
security device and the device are communicatively coupled to the
first network via the router.
17. The storage device or storage disc of claim 14, wherein
determining whether the first data packet is associated with the
threat includes determining whether the first data packet violates
a behavioral rule or a reconnaissance rule.
18. The storage device or storage disc of claim 14, further
including instructions which when executed, cause the machine to at
least determine whether a source Internet Protocol (IP) address of
the first data packet is on a second network, the second network
including the security device and the device.
19. The storage device or storage disc of claim 18, wherein the
second data packet is an ARP packet, wherein a source of the ARP
packet includes an IP address of the device and a synthetic media
access control (MAC) address, wherein the synthetic MAC address is
not in use on the second network.
20. The storage device or storage disc of claim 19, wherein a
destination of the ARP packet includes an IP address of the router
and a MAC address of the router.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent arises from a continuation of U.S. patent
application Ser. No. 13/603,388, filed Sep. 4, 2012, entitled
"Logical/Physical Address State Lifecycle Management," which arises
from a continuation of U.S. patent application Ser. No. 10/676,505
issued as U.S. Pat. No. 8,260,961 filed Oct. 1, 2003, entitled
"Logical/Physical Address State Lifecycle Management," which claims
the benefit of priority based on U.S. Provisional Patent
Application Ser. No. 60/415,290, filed Oct. 1, 2002, entitled
"System and Method for Detecting and Managing Network Intrusion."
U.S. patent application Ser. No. 13/603,388, U.S. patent
application Ser. No. 10/676,505, and U.S. Provisional Patent
Application Ser. No. 60/415,290 are hereby incorporated by
reference in their entireties.
[0002] Portions of this patent application contain materials that
are subject to copyright protection. The copyright owner has no
objection to the facsimile reproduction by anyone of the patent
document, or the patent disclosure, as it appears in the Patent and
Trademark Office file or records, but otherwise reserves all
copyright rights whatsoever.
FIELD OF INVENTION
[0003] This invention, in general, relates to a system and method
for managing the lifecycle of logical and physical addresses. More
specifically, this invention relates to initializing an address
state to unknown when the address state is not defined and changing
the address state when a communication is targeted to the
address.
BACKGROUND OF THE INVENTION
[0004] Global networking of computers has greatly impacted
business. As the number of computers linked to networks grows,
businesses increasingly rely on networks to interact. More and more
people use email, websites, various file transfer methods, and
remote office applications, among others, to facilitate business
transactions and perform job related tasks.
[0005] These applications and uses still rely on early network
addressing technologies and flow control protocols to transmit data
packets across networks. For example, the Internet Protocol (IP) is
an addressing protocol for referencing remote devices on a network.
The protocol is implemented to include a packet header that
contains bits representing an address of the source, an address of
the target, and various other parameters associated with the
packet. The Address Resolution Protocol (ARP) is used to reconcile
physical addresses on local segments of a network with IP
addresses. Other protocols are used for flow control including TCP
and UDP. These protocols may be used to control the flow of packets
across a network including subdividing and reassembling the
packets. TCP also includes methods for: verifying the arrival of a
packet. Other protocols include ICMP, IPX, SPX, NetBios, and ARP,
among others. Historically, these protocols were designed for use
on a trusted network and as such do not include many security
features. To address this problem, newer protocols are designed to
include some security measures. However, at present, the global
Internet and many local area networks predominantly use older
protocols with various vulnerabilities.
[0006] Hackers and malfeasants take advantage of the weaknesses in
these protocols to disrupt, infiltrate, or destroy networked
devices. These attacks include worms, viruses, denial-of-service,
and infiltration attacks, among others. Worms are self-replicating
programs that infect computers. In some cases, these worms take
advantage of the trusting relationships between computers to
infiltrate network and send network data to the attacker. Viruses
infect files and utilize vulnerabilities of programs that interpret
the files to propagate. A virus may also function to erase data.
Denial-of-services (DoS) attacks often limit the network activity
of a target computer by inundating the target with requests or
messages. In one example, an attacking computer or set of computers
may send a plethora of low level pings to the target device. If the
pings include a non-existent return address, the target machine
could send a response message and pause over a timeout period for a
response. In attempting to respond to the pings, the machine
effectively denies network access to other applications.
[0007] Infiltrating attacks often circumvent password security and
gain access to files. Once the attacker has access, they may steal
private information such as credit card or social security numbers.
Moreover, they may damage valuable data, install a worm or spying
program, or install programs to utilize computational capacity.
[0008] The FBI reports that millions of dollars are lost each year
as a result of these attacks. In the "2002 Computer Crimes and
Security Survey," as much as 90% of the Fortune 2000 companies
reported breaches in computer security. According to the survey,
each successful attack cost corporations an average of $2.1
Million. The losses include lost data, employee time used in
recovering data, delays in existing projects, and damage to
equipment. Fifty-five percent of the companies surveyed reported
denial-of-service attacks, 70% reported infiltration and vandalism
attacks, and twelve percent reported theft of transaction
information.
[0009] Hackers use various tools and methodologies to discover
vulnerable devices and interact with them. These tools include
address scanners, port scanners, worms, and packet formulation
programs, among others. For example, a hacker may send
reconnaissance packets to a local network segment in search of a
computer or device. Once a device is found, the hacker may scan the
ports on the device in search of a vulnerable port.
[0010] Several approaches exist for protection against hackers.
Typically, these protections are defensive shield-like methods. The
most common are firewalls, intrusion detection systems (IDS), and
anti-virus software. Firewalls are devices typically placed as
shields between a local network and the global network. Firewalls
are the most common form of network protection. They perform their
function by limiting communication between the local network and
global network in accordance with various filters and rules.
Typically, network traffic is either blocked or permitted based on
rules regarding protocols, addressing, and port number. These
filters are infrequently changed and can unintentionally encumber
certain permissible network traffic while permitting unwanted
traffic.
[0011] Intrusion detection systems detect intrusions or attacks and
report these attacks to network security. The systems predominantly
use packet signatures to evaluate network packets. However, these
systems have been shown to be unreliable as they can generate false
positive results. Often, the systems collapse under the weight of
the data they collect. Further, these systems may not detect
packets with signatures that are not found in their signature
database, resulting in false negatives as well. Moreover, these
systems often present the data to network security in a format that
prevents timely response to threats.
[0012] Similarly, anti-virus software typically relies on file
signatures to detect viruses. As such, frequent updates are
required to maintain a current database of virus signatures. If an
undocumented virus enters the network, the anti-virus software will
likely fail.
[0013] Many network security systems suffer from deficiencies in
detecting and preventing attacks on a network. Many other problems
and disadvantages of the prior art will become apparent to one
skilled in the art of networks security systems after comparing
such prior art with the present invention as described herein.
SUMMARY OF THE INVENTION
[0014] Aspects of the invention may be found in a system, method,
and computer-readable medium for managing logical and physical
address state lifecycles. The method can include assigning a
respective state of unknown to a first address of multiple
addresses when the respective state of the first address has not
been assigned. The method further includes changing the respective
state of the first address when a communication is targeted to the
first address. The addresses can include all valid logical
addresses for a corresponding set of devices on a segment of a
network, or all valid physical addresses for a corresponding set of
devices on a segment of a network.
[0015] The respective state of the first address can be changed to
used when the communication indicates that the first address
corresponds to a device in use. The respective state of the first
address can be changed to unfulfilled when the communication
includes an address resolution protocol request sent to a device
having the first address when a time limit for a response to the
address resolution protocol request has not expired. The respective
state of the first address can be changed to omitted when the first
address corresponds to a device, and communication with the device
is omitted from being observed. In addition, the respective state
of the first address can be changed to omitted when the respective
state of the first address is programmed to be omitted from the
changing.
[0016] The respective state of the first address can be changed to
virtual when the communication is received at the first address
when the respective state of the first address is unfulfilled, and
a time limit for responding to the communication expires before a
response is sent by the first address. The respective state of the
first address 9 can be changed to unknown when the respective state
of the first address is not unknown, and the first address does not
participate in the communication within a time limit. The
respective state of the first address can be changed to automatic
when an automatic reply is programmed to be sent to a second
address when the first address receives a packet from the second
address.
[0017] Additional aspects of the invention may be found in a system
for managing logical and physical address state lifecycles. The
system may be a computational device including a processor or
network interface and memory or computer-readable medium, among
others. The device may or may not include a user interface.
Further, the device may have various data and instructions
associated with various methods for managing logical and physical
address state lifecycles. These data may include an ARP request
queue, an IP state table, a frequency table, an ARP table, a watch
list, a threat list, a synthetic physical address table, and a
communications stream table, among others. The device may also
include packet instructions for evaluating reconnaissance rules,
behavioral rules and other rules, among others. Further, the system
may include software or computer interpretable instructions for
performing various methods associated with maintaining the data in
the tables and collecting the data for the tables.
[0018] As such, a system, method, and computer-readable medium for
managing logical and physical address state lifecycles are
described. Other aspects, advantages and novel features of the
present invention will become apparent from the detailed
description of the invention when considered in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] For a more complete understanding of the present invention
and advantages thereof, reference is now made to the following
description taken in conjunction with the accompanying drawings in
which like reference numbers indicate like features and
wherein:
[0020] FIG. 1 is a schematic block diagram depicting a network and
network devices according to the invention;
[0021] FIG. 2 is a schematic block diagram depicting an exemplary
embodiment of a network as seen in FIG. 1;
[0022] FIG. 3 is a block flow diagram depicting an exemplary method
for use by the system as seen in FIG. 1;
[0023] FIG. 4 is a block flow diagram depicting an exemplary method
for use by the system as seen in FIG. 1;
[0024] FIG. 5 is a block flow diagram depicting an exemplary method
for use by the system as seen in FIG. 1;
[0025] FIG. 6 is a block flow diagram depicting an exemplary method
for use by the system as seen in FIG. 1;
[0026] FIG. 7 is a block flow diagram depicting an exemplary method
for use by the system as seen in FIG. 1;
[0027] FIG. 8 is a block flow diagram depicting an exemplary method
for use by the system as seen in FIG. 1;
[0028] FIG. 9 is a block flow diagram depicting an exemplary method
for use by the system as seen in FIG. 1;
[0029] FIG. 10 is a block flow diagram depicting an exemplary
method for use by the system as seen in FIG. 1;
[0030] FIG. 11 is a block flow diagram depicting an exemplary
method for use by the system as seen in FIG. 1;
[0031] FIG. 12 is a schematic depicting an exemplary embodiment of
an ARP queue as used in the method as seen in FIGS. 5-11;
[0032] FIG. 13 is a block flow diagram depicting an exemplary
method for use in evaluating the ARP queue as seen in FIG. 12;
[0033] FIG. 14 is an exemplary embodiment of a watch list as used
in the methods as seen in FIGS. 5-11;
[0034] FIG. 15 is a block flow diagram depicting an exemplary
method for use in evaluating the watch list as seen in FIG. 14;
[0035] FIG. 16 is a schematic depicting an exemplary embodiment of
a multidimensional frequency table for use in the methods of FIGS.
5-11;
[0036] FIG. 17 is a schematic depicting an IP state table for use
in the methods as seen in FIGS. 5-11;
[0037] FIG. 18 is a schematic diagram depicting a table for use in
the method as seen in FIGS. 5-11;
[0038] FIG. 19 is a schematic of an exemplary embodiment of a
message header for use in the methods as seen in FIGS. 5-11;
[0039] FIG. 20 is a schematic of an exemplary embodiment of a
communications stream table for use in the methods as seen in FIGS.
5-11;
[0040] FIG. 21 is a block diagram depicting an exemplary embodiment
of a network security device for use in the system as seen in FIG.
1;
[0041] FIG. 22 is a block flow diagram depicting an exemplary
method for use by the system as seen in FIG. 1;
[0042] FIG. 23 is a block flow diagram depicting an exemplary
method for use by the system as seen in FIG. 1;
[0043] FIG. 24 is a block flow diagram depicting an exemplary
method for use by the system as seen in FIG. 1;
[0044] FIG. 25 is a block flow diagram depicting an exemplary
method for use in the system as seen in FIG. 1;
[0045] FIGS. 26A and 26B are block flow diagram depicting exemplary
methods for use in the system as seen in FIG. 1; and
[0046] FIG. 27 is a schematic diagram depicting an exemplary
embodiment of a network as seen in FIG. 1.
DETAILED DESCRIPTION
[0047] In attempting to contact and infiltrate networks, attackers
or programs implemented by the attackers act with characteristic
behaviors to determine the address of computers on local segments
and communicate with them. These behaviors may be used, separately,
or in combination with packet signatures and filters, to identify
the attackers as threats. Once identified, communication between
the network and the attacker may be controlled, preventing further
damage. One method is to deceive the attacker, preventing them from
either perceiving the existence of a machine or redirecting their
communication to an alternative device such as a security device or
sacrificial computer.
[0048] FIG. 1 is a schematic block diagram depicting a network
according to the invention. An area network 14 is connected to a
global network 12. A firewall 16 may or may not be placed between
the global network 12 and the area network 14. Connected to the
area network 14 may be routers 20, switches 22, security devices
24, servers 26, workstations 28, portable devices 30, and gateway
devices 34, among others. The network 14 has either a security
device 24 or some other computational device that acts to detect
attacks on the area network 14 and mask other devices attached to
the area network 14 from the attacker. The attacker may be an
attacker 18 connected to the global network 12 or an attacker 32
connected to the area network 14. However, these components may or
may not be included in the system, and may be together, separate,
or in various combinations, among others.
[0049] The global network 12 may take various forms and may
communicate with various protocols including IP, TCP, UDP, ICMP,
HTTP, and FTP, among others.
[0050] Area network 14 may take various forms including Ethernet,
Wireless Ethernet, Token rings, Apple Talk, or various combinations
of these, among others. In one exemplary embodiment, the area
network 14 may be an Ethernet network that resolves logical and
physical network addresses using an address resolution protocol
(ARP). The ARP resolves the addresses between Internet Protocol
(IP) addresses and physical address such as media access control
(MAC) addresses.
[0051] The security device 24 or some other computational device
such as a server 26, workstation 28, routers 20, switches 22, or
gateways 34, among others, may function to detect attacks on the
area network 14. Singly or in combination these devices may hold
and compile a list of devices, MAC addresses, or source IP
addresses of devices that represent a threat to the system. Using
this list, the device or devices may capture packets, compare the
MAC address, source W address, or target IP address, with known
threats to the system, and take steps to control or prevent
communication with vulnerable devices.
[0052] For example, the device may create ARP packets with
synthetic hardware addresses associated with the IP addresses of
either local devices or attacking devices. In this manner, the ARP
tables may be altered, causing packets to be sent across the
network to physical addresses other than those targeted by the
communication.
[0053] For example, the synthetic hardware addresses may be MAC
addresses that are not in use by devices on the area network 14.
Alternately, the synthetic hardware address may be the address of a
sacrificial computer, defense system or security system, among
others.
[0054] FIG. 2 is a schematic block diagram depicting an exemplary
embodiment of the system as seen in FIG. 1. The router 38 may or
may not be connected to the global network 37 through a wide area
network 39: The router 38 routes traffic from the global network 37
or wide area network 39 to various devices on a local area network
or a local segment of a network 48. The devices on the segment may
include workstations 40 and 46, a server 42, a gateway 41, and a
security device 44. However, various embodiments of network
segments may be envisaged.
[0055] In this exemplary embodiment, attacker 36 may send network
packets through a global network 37 to router 38. Router 38 may
then forward the network packet to the local network 48 where the
addressed device receives the communication. Security device 44 may
capture these packets, determine whether the packets were sent by
an IP address of a device of interest or that represents a threat,
and act to control communications between the attacker 36 and the
devices on the local segment 48.
[0056] In one exemplary embodiment, a security device 44 may detect
an attack on the local segment 48. The device may then create ARP
packets that include a synthetic physical address, and send those
ARP reply packets to a gateway device or other computational
device, effectively altering the ARP table in that device.
[0057] FIG. 3 is a block flow diagram depicting a generic method
for detecting network incursion. The method includes capturing
network packets from the local segment. From these packets tables
associated with the state of IP address, the nature of the packets
and communications streams may be established. This data may be
compared to various rules to determine if an attack is occurring.
In the event that an attack is occurring, the system may set a flag
or parameter indicating that occurrence and notify personnel or
implement a defense mechanism.
[0058] Various methods for identifying threats and therefore
addresses of devices that represent these threats may be envisaged.
One exemplary embodiment is seen in the block flow diagram of FIG.
4.
[0059] The method 90 begins with the capturing of a network packet
from the local segment as seen in a block 92. This packet may be a
network packet comprising data for various protocols including ARP,
TCP, IP, HTTP, UDP, or FTP, among others. The method may then
decode the packet as seen in a block 94. With the decoded packet,
system determines whether the packet represents is of interest or a
known threat and may implement a control mechanism such as
adjusting an ARP table in response. For example, the system may
compare the source or target IP address to a list of known
threatening devices. However, alternate methods may be used in
determining the threat.
[0060] The system may then process various parts of the packet or
packet formats in the appropriate manner. For example, the system
may process ARP packets as seen in a block 98 and TCP/IP packets as
seen in a block 100. However, the method may be configured to
process packets using a variety networking and data linking
protocols.
[0061] The system may then compare the processed information and
packet to a set of, reconnaissance rules as seen in a block 102.
Multiple reconnaissance rules can be used. For example, determining
if the packet strictly conforms to the protocol specification for
size and configuration, identifying if the packet flags represent
any illegal combinations used to circumvent firewalls, or
determining if the packet continues a pattern of packets that
cumulatively represents a reconnaissance event. In this manner, the
system may determine whether a source computer is behaving in an
appropriate manner, and if not, may place the address of the
computer on a watch list.
[0062] Next, the system may check for target violations as seen in
a block 104. These violations may include a packet addressed for an
IP address known not to be in use, a packet addressed to a port
that is known to be closed, or an ARP request sent to an IP address
that does not provide a corresponding reply.
[0063] The system may also update or add a communication stream to
a communication stream table as seen in 106. The communications
stream table may be one or more tables recording information
associated with the communications protocol used by the packet, the
addresses of the devices associated with the packet, the direction
of the packet, and the time of the last packet sent, among others.
For example, the system may maintain several tables, each uniquely
associated with a communications protocol. These tables may then
track interactions with devices on the area network. In this
manner, the system may track a communication stream and determine
whether systems or devices are behaving appropriately.
[0064] As seen in a block 108, the system may compare the behavior
of various devices to a set of behavior rules to determine whether
a device as represented by its IP address is acting as a trusted
device should. For example, a device scanning multiple IP addresses
may represent a threat. Or, a device may begin receiving traffic on
a port that has historically been closed. Or, the device may
initiate communication on ports representing services that are not
installed on the device. In all cases, the device would be added to
a watch list. A more detailed embodiment of this method may be seen
in FIGS. 5-11.
[0065] As seen in FIG. 5, the system may capture a packet 112 and
decode the packet as seen in a block 114. The system may first test
to determine whether a threat exists to the system. This test may
be implemented as a flag in a data set or a test for IP addresses
in a list of known threats, or in various other manners. For
example, if a device with an IP address known to be a threat has
active communications streams in one or more communications streams
tables, the system may change a flag or variable to represent the
existence of a threat condition. Over time, if communication from
the threatening device ceases, the system may return to a state` of
no threat. If no threats exist, then the system may move to the
processing of ARP packets as denoted by a block A.
[0066] However, if a threat exists, the system may test the source
IP address of the packet as seen in a block 118, the target IP
address as seen in a block 120 and the target physical address as
seen in a block 122. If the target IP address or source IP address
are determined to represent threats, the system may invoke a
defense mechanism as seen in block 124. This defense mechanism may
include managing communications through MAC layer routing and
filtering. Additional defense methods may be seen in FIGS. 25, 26A,
and 26B.
[0067] To determine whether the addresses represent a threat, the
system may compare the addresses to a list of addresses of known
threats. Similarly, if the target physical address is synthetic the
system may invoke a defense as seen in a block 124. To determine
whether the physical address is synthetic, the system may compare
the address to a list of known synthetic addresses, or a list of
known addresses in use on a local segment. If no threat is found
and the physical address is not synthetic the system may continue
as seen in a block A.
[0068] In an alternate embodiment, the system may determine whether
the packet with the synthetic physical address represents a threat.
If the packet is non-threatening, the packet may be reformulated
and sent to the intended device.
[0069] FIG. 6 depicts a processing of packets that utilize the
address resolution protocol (ARP). The address resolution protocol
includes protocols for several message types. Two of the types
include requests and replies. Generally, a request from one device
has a corresponding reply from another device. A lack of a
corresponding relationship may indicate the presence of an
attack.
[0070] Once the packet is tested for threats or synthetic
addresses, it may be tested to determine whether the packet uses
ARP. If the packet does not use ARP, a system may move on to the
processing of TCP/IP packets. However, if the packet is an ARP
packet, the packet may be tested for various types of ARP packets,
and processed accordingly. For example, if the packet is an ARP
request as seen in a block 184, the packet may be further tested to
determine whether the packet is gratuitous as seen in a block 136.
A gratuitous ARP request is typically used to announce to a network
the presence of a new device and its address. If the packet is a
gratuitous ARP, the system may continue on to the processing of
TCP/IP packets.
[0071] However, if the packet is not gratuitous, the system may
test to determine whether an identical ARP request is found in an
ARP queue as seen in a block 138. If an identical request is found,
the packet may continue on to TCP/IP processing. However, if the
packet is not in the queue, the ARP request may be added to the ARP
request queue as seen in a block 140, and the state of target IP
may be changed to "unfulfilled" in an IP state table. In this
manner, state data associated with requests may be stored while
waiting for an expected reply.
[0072] If the packet is an ARP reply as seen in a block 144, the
system may test for a corresponding ARP request in a queue as seen
in a block 146 and remove the corresponding ARP request from the
queue as seen in a block 148. In each case, the packet may be
forwarded for TCP/IP processing as denoted in block C. An exemplary
embodiment of an ARP request queue is seen and discussed in
relation to FIG. 12. An exemplary embodiment of an IP state table
is seen and discussed in relation to FIG. 17.
[0073] Once ARP packets have been processed, or if the packets are
determined not to be ARP packets, then they may be forwarded to
TCP/IP processing as shown in FIG. 7. The packet may first be
tested to determine whether the packet is a TCP/IP packet. If it is
not, it may be forwarded to processing under alternate protocols or
a subsequent packet may be captured and the method re-started. For
example, this may be the case for networks with IPX/SPX
communications.
[0074] If the packet is a TCP/IP packet, the source IP address is
sought in a frequency table as seen in a block 154. If the source
IP address is not found in the frequency table it may be added as
seen in a block 156. In either case, the system tests the
destination IP address to determine whether it is in the frequency
table. If the destination IP address is not in the frequency table,
it may be added. In either case, the system may update packet
frequency values in accordance with the frequency table as seen in
a block 162. An exemplary embodiment of a frequency table is seen
and discussed in relation to FIG. 16.
[0075] FIG. 8 is an exemplary method for determining whether a
packet is designed for reconnaissance in a local network segment.
For each rule in a reconnaissance rule list, as seen in a block
172, a system may test a packet to determine whether it violates
the rule as seen in a block 174. If the packet violates a rule, a
system may note the rule and place the IP source on a watch list as
seen in a block 178. A system may then continue to test rules as
seen in a loop from block 180 to 172. Once all the rules are
tested, the system may continue on as seen in block E. Some
examples of common reconnaissance rules are: packets with
parameters that violate the protocol definition, packets with
inappropriate flag configurations, or packets with unusual
sequencing or fragmentation.
[0076] FIG. 9 is an exemplary method for testing a target
violation. This method tests to determine if a packet has a
destination address that is not in use, a port that is known to be
closed, or an ARP request with an IP address that does not provide
a corresponding reply. The system tests the packet to determine
whether it is an ARP request as seen in a block 192. If the packet
is an ARP request, a system checks the target IP state to determine
whether it is unfulfilled, as seen in a block 194. If it is, the
system continues as seen in a block F. However, if the target IP
state is not unfulfilled, the system notes a rule violation as
denoted by the block 200 and places the source IP address on a
watch list as seen in a block 202. If the packet is not an ARP
request, the system tests the target IP address of the packet to
determine whether it is in use as seen in a block 196. If the
target IP address is in use, the system checks to see if the target
port on the target device is known to be open as seen in a block
198. If the target IP address is not in use or the target port is
not known to be open, the system notes a rule violation--as
seen--in a block 200, and places the source IP address of the
packet on the watch list. The system then continues as denoted by a
block F.
[0077] FIG. 10 is an exemplary method for updating a communication
stream table from block F. The packet is tested to determine
whether it is included in the communication stream table as seen in
a block 212. If it is not, it is added to the table as seen in a
block 214. If it is, the table is updated with the communication
stream time and direction, as seen in a block 216. The system then
continues as seen in a block G.
[0078] Once the communications tables are updated, the system may
check for behavioral rule violations. FIG. 11 is an exemplary
method for testing whether a behavior rule is violated. For each
behavior rule, the system checks the frequency data in the
frequency table to determine whether a cell, row, or column in a
multi-dimensional array has violated a behavioral rule boundary as
seen in a block 234. If the boundary has been violated, the rule is
noted as seen in a block 236 and the source IP address is placed in
a watch list as seen in a block 238. Once the rules have been
tested, the system returns as seen in a block H and continues to
collect a subsequent packet, decode it, and process it in the
manner seen in FIGS. 5-11.
[0079] FIG. 12 is an exemplary embodiment of an ARP request queue.
The ARP request queue may include a source IP address, a target IP
address, a source MAC address, and the time associated with an ARP
request. If a corresponding reply to the request is not received
within a specified programmable period of time, the ARP request may
have been initiated by a device that represents a threat.
[0080] FIG. 13 is an exemplary method in which the time is compared
to a set threat limit as seen in a block 254. If the time exceeds
the threat limit, the source IP address is placed on a watch list
as seen in a block 256. This step may be repeated for each item in
the queue as seen in a block 252.
[0081] FIG. 14 represents an exemplary embodiment of a watch list.
The watch list may include a listing of potentially threatening
devices. The watch list, for example, may contain a source IP
address, a target IP address, a source physical address, the time
the packet was sent; and the denotation of a rule that was
violated, among others.
[0082] FIG. 15 is an exemplary method for determining whether items
in a watch list represent a threat. For each item in the watch
list, the system may determine whether it is necessary to elevate
or escalate the item to a threat as seen in a block 274. This
decision may be based on the type or frequency of rule violations,
or various combinations of rule violations and frequency
violations. If it is necessary to escalate the watch list to a
threat, the system may add the source IP address to a threat list
as seen in a block 276. However, various methods may be
envisaged.
[0083] Conversely, it may become apparent over time that a source
IP address does not constitute a threat, in which case it can be
de-escalated. For example, a typographical error may have been made
in a destination address, without the intent or function of
generating a threat. In such an instance, de-escalation would be
the appropriate way to return the system to a normal condition.
[0084] FIG. 16 represents an exemplary embodiment of a frequency
table. In this exemplary embodiment, a multi-dimensional table is
shown with a vertical axis of IP addresses, a horizontal axis of
time, and another depth axis. The vertical axis may be a listing of
IP addresses. In this exemplary embodiment, the listing of IP
addresses includes all source addresses of packets.
[0085] The time axis may represent bins of varying periods. For
example, these periods may represent the time since the last packet
associated with the IP address or ongoing time. The number of bins
may be set by a user of the system and the size or period
represented by the bins may be set and varied along the axis.
[0086] Looking at this two-dimensional face, the IP addresses and
time, the number of packets sent by the IP address may be tallied
over time to produce a frequency table of packets associated with
the IP address. Various methods may be used to normalize the
frequency table or adjust the values in the various time bins over
time or in association with the arrival or transmission of
subsequent packets. In one exemplary embodiment, each bin
(representing a period less than the period of the most recent
packet may be decremented uniformly or with some distribution.
[0087] In the multi-dimensional case, other axes may be represented
by packet size, destination IP addresses, protocols, message types,
and other characteristics. Various behavioral rules may then be
established that identify threats by exceeding the boundaries
assigned to various cells, columns, or rows. For example, if a
single source as represented by its IP address were to frequently
send packets into the network to multiple unused IP addresses, that
source may be identified as a potential threat seeing the addresses
of devices. In other example, if various sources flood a single IP
address with messages, it may be determined that a denial of
services attack is occurring.
[0088] FIG. 17 represents an IP state table. Recall that when an
ARP request is identified and added to the ARP request table, the
IP state of the target IP address or device is set to "unfulfilled"
in an IP state table. Traditionally, an IP address may be in use or
not in use. This system, however, tracks various additional states
including omitted, automatic, used, unfulfilled, virtual, and
unknown. The system uses the IP state table to monitor IP addresses
associated with the local network segment and those addresses on
the threat list. The IP state table provides the system with a
method of monitoring the state of IP addresses on a dynamically
changing network segment.
[0089] In the case of an ARP request sent to a target IP address,
the system sets the state of the target IP address to unfulfilled.
If a reply to the ARP request is not received by the source IP
address within a given period of time, the target IP address state
may be set to virtual. It is possible that the target address is
not in use. If a packet is sent from an IP address that is marked
as unknown, the system attempts to ascertain the true state of the
IP address through various active and passive means. When the true
state of the IP address is determined, the state table is updated
with the appropriate state value.
[0090] Since communication between devices is perceived through
packets, the state of the network may be tracked through the IP
State table. FIG. 18 depicts a conceptual chart of communications.
An IP address may be in use or not in use. A packet may be sent
from a source IP address known to be in use to a destination IP
address. If the destination IP address is not in use, the sending
of the packet to that destination address may be a first clue in
perceiving network incursion. Similarly, a sending of a packet from
a source known not to be in use may indicate address spoofing by an
intruder.
[0091] However, a single packet such as an ARP request does not
indicate whether the destination IP address is in use. An ARP reply
would indicate the use of the destination address. Failure to reply
may indicate that the destination address is an unused IP address.
However, a device associated with the destination address may have
been busy. As such, the devices may be categorized in the state
table in categories indicative of knowledge or expectation obtained
from observation of other communication with those devices.
[0092] Turning to FIG. 19, an ARP reply packet 290 is depicted. In
this exemplary embodiment, the ARP reply packet 290 is depicted as
having a source IP address 292 with an associated hardware address
294. The associated hardware address is, in this example, a
synthetic hardware address. The message 290 also contains a
destination IP address 296 and a hardware address 298 associated
with the destination IP address 296. If such a message were sent on
a local network segment, the ARP table associated with the
destination IP address 296 and hardware address 298 would be
adjusted. Any subsequent communications sent to the source IP
address from the device associated with the destination address
would be sent to an incorrect hardware address, preventing
communications with the source device, represented in the ARP reply
packet 290. The destination device may be a server, gateway,
workstation, or other network device. In this manner,
communications may be controlled between attacking devices and
devices on the local segment of the network.
[0093] Turning to the next figure, FIG. 20 depicts an exemplary
embodiment of a communications stream table. The communications
stream table is one or more tables tracking communications between
devices. In one exemplary embodiment, the communications stream
tables are tables that each track communications associated with a
single protocol. For example, tables may be used to track ICMP,
TCP, UDP, and ARP communications. The tables may be associated with
the addresses of two devices associated with the number and
frequency of data, direction, statistical information, and time of
last `packet. The communication streams tables may be periodically
polled to aid in setting the state of IP addresses in the IP state
table. For example, if the age of a communications stream exceeds
some value, the system may attempt to contact the device associated
with the IP address to determine whether it is active or the
address is in use. If the device does not respond, the device may
be removed from the IP state table. Furthermore, the communications
stream tables may be updated if a communications stream becomes
stale.
[0094] FIG. 21 is an exemplary embodiment of a security device for
performing the functionality described in the various methods
herein. The security device 310 may include a processor 312, a
network interface 314, a memory 316, and a user interface 340. The
device 310 may also include an ARP request queue 318, an IP state
table 320, a frequency table 322; an ARP table 324, a watch list
326, a threat list 328, packet reconnaissance rules 330, behavior
rules 332, a MAC address table 334, one or more communications
stream tables 336, and various instructions 338, among others.
However, each of these elements may or may not be included
together, separately, or in various combinations, among others. For
example, the data and instructions may reside on a single device or
on various devices, among others.
[0095] The processor 312 may take various forms including various
microprocessors, computational circuitries, and controllers, among
others. The processor 312 may interpret various instructions or
data and function accordingly.
[0096] A network interface 314 may take various forms. These forms
may include an Ethernet NIC, a serial cable, a USB port, an
AppleTalk connection, and a wireless Ethernet connection, among
others. The network interface may function to aid in capturing
network packets, sending appropriate messages across the network,
and communications with other devices, among others.
[0097] The memory 316 may take various forms including ROM, RAM,
flash memory, disc drives, floppy drives, CD-ROM's, and DVD ROM's,
among others.
[0098] The system 310 may or may not include a user interface 340.
This user interface may take various forms including a hand-held
device, a keyboard, a monitor, a mouse, and remote access
interfaces, among others.
[0099] The ARP request queue 318 is a listing of ARP requests and
the time they were sent. The system attempts to match ARP requests
with a corresponding ARP reply. If no match is found over a given
period of time, a rule may be violated and the source IP of the ARP
request may be placed on a watch list. The table may take various
forms including a database file, a tab delimited file, a
spreadsheet, a text file, a data file, among others.
[0100] The IP state table 320 may include a listing of IP addresses
and an associated state. Generally, the state is either active or
inactive. However, the system applies varying states to the IP
address including omitted, automatic, used, unfulfilled, virtual,
and unknown, among others. The table may take various forms
including a database file, a tab delimited file, a spreadsheet, a
text file, or a data file, among others.
[0101] The frequency table 322 may take various forms, including
that shown in FIG. 16. The frequency table may store data
associated with an IP address and the frequency of packet delivery
over time. Further, the table may be structured as a
multi-dimensional data set with other axes including protocols,
packet size, communications type, and` destination address, among
others. The frequency table may take various forms including a
database file, a tab delimited file, a spreadsheet, a text file, a
data file, among others.
[0102] The ARP table 324 is typically a listing of IP addresses and
an associated physical address on the network. Generally, most
devices connected to the network maintain an ARP table. This system
may communicate with various devices on a network to adjust values
maintained in the various ARP tables.
[0103] The watch list 326 may take the form as seen in FIG. 14. The
watch list may include a listing of IP addresses that have violated
various rules. IP addresses listed in the watch list may be
elevated and identified as potential threats, and placed in a
threat list 328. The threat list may be a listing of IP addresses
associated with devices that are known to be threats to the system.
This list may be used to determine which packets entering the local
network segment represent a threat and to prevent those packets
from accessing devices on the local segments.
[0104] A device 310 may include packet reconnaissance rules 330.
These rules may be used to determine from the packet information
whether the packet is designed to reconnoiter on the local segment.
If the packet violates these rules, the source IP address for the
packet may be placed on the watch list.
[0105] The behavioral rules 332 may be rules, boundaries, or
thresholds that are compared to frequency table 322. If cells,
columns, or rows violate these boundaries or thresholds, the IP
address associated with the violation may be marked as a potential
threat and placed on a watch list or the threat list 328.
[0106] The system may also include a table of synthetic MAC
addresses. Alternately, the system may include a version of an ARP
table associating IP address with real physical addresses, or a
combination of both synthetic MAC addresses and real physical
addresses. It should be understood through this description of an
illustrative embodiment, that although the use of tables is
mentioned here, the present invention may use other types of
persistent, logically addressable storage mechanisms for the
different types of addresses. In either case, the table may be used
to determine whether an address is a synthetic address and be used
in re-creating or re-structuring the packets for delivery to the
appropriate physical device.
[0107] The Communications stream table or tables 336 may take
various forms including a database file, a tab delimited file, a
spreadsheet, a text file, a data file, among others. The
communications stream tables 336 may track communications between
devices as discussed in relationship to FIG. 20.
[0108] The instructions 338 may include various operating
instructions and computer-implemented instructions for implementing
the methods herein, among others. These instructions may take the
form of interpretive instructions, programs, and additional data,
among others.
[0109] However, these elements may or may not be included together,
separately, or in various combinations, among others. For example,
various devices may be combined to function and store the data and
instructions described above.
[0110] FIG. 22 is another exemplary method for perceiving threats
to the system. Hereto the system captures the packet as seen in a
block 354. The system determines whether the packet is an ARP
packet as seen in a block 356. The packet may be an ARP request or
an ARP reply as seen in a block 358. From this it may be determined
whether the source IP address is a threat as seen in a block 362,
or not a threat as seen in a block 360.
[0111] Further, the packet may be tested to determine whether it is
a TCP/IP packet as seen in a block 364. If it is not a TCP/IP
packet, it may be ignored as seen in a block 366 or forwarded for
processing in accordance with other packet protocols. If the packet
is a TCP/IP packet, a destination IP address may be tested as seen
in a block 368. If the destination IP address is not in use, the
source IP address may represent a threat as seen in a block 370. If
the destination IP address is in use, the packet may be subjected
to further tests. For example, the packet may be tested to
determine whether it represents a reconnaissance packet as seen in
a block 372. If it is a reconnaissance packet, the source IP
address may be a threat as seen in a block 374.
[0112] Further, the packet may be tested to determine whether it
violates a frequency rule as seen in a block 376 or a target port
frequency rule as seen in a block 380. In either case, a violation
of a rule may indicate that the source IP address is a threat as
seen in blocks 378 and 382, respectively. Further, the packet may
be tested to determine whether it violates the aggregate rules as
seen in a block 384. If it does violate these rules, it may
represent a threat as seen in a block 386. However, if the packet
does not violate the rules, it may not represent a threat as seen
in a block 388.
[0113] FIG. 23 is an exemplary method for creating and maintaining
an IP address state table. Hereto the system may capture a packet
as seen in a block 394. The system may test to determine whether
the source IP state is known. If it is not known, the system may
set the source IP state as seen in a block 398 and note the time as
seen in a block 400. If it is known, the system may test to
determine whether the destination IP address state is known. If
that state is not known, the destination IP address state may be
set as seen in a block 406, and the time noted, as seen in a block
408. Further, the system may test the packet configuration to
determine whether the source IP state requires change as seen in a
block 412. If the source IP state is to be changed, the system may
change these source IP states as seen in a block 414 and note the
time as seen in a block 416. In either case, the system may further
test to determine whether the destination IP state requires change
as seen in a block 418. If change is required, the system may
change the state of the target IP address as seen in a block 420
and note the time as seen in a block 422.
[0114] FIG. 24 represents adjustment of an IP address state. In
this case, the system checks the time as seen in a block 434. The
system determines whether there is an appropriate time to check the
IP state as seen in a block 436. If it is not, the system does
nothing as seen in a block 438. If it is time to check the states,
the system checks each entry on an IP state table as seen in a
block 440. If enough time has elapsed, as seen in a block 442, the
system adjusts the IP state as seen in a block 446.
[0115] FIG. 25 is an exemplary embodiment of a defense method as
described in relation to FIG. 5. The system may accept a packet as
seen in a block 472. The system may test the source IP address of
the packet to determine whether it represents a threat. If the
source IP address does not represent a threat, the system may
accept a subsequent packet. If the source IP address does represent
a threat, the system may test the packet for various protocols and
packet types as seen in blocks 476, 480 and 484. For example, if
the packet as an ARP request from a known threat, the system may
send an appropriately crafted ARP reply. The reply fools an
attacking computer into believing that a computer exists at the
target IP address and sets the stage to allow for future
connections.
[0116] If the packet is an ICMP echo request as seen in a block
480, the system may send an appropriately crafted ICMP echo reply
as seen in a block 482. In this case, an attacker may be performing
reconnaissance. An appropriate response makes the attacking
computer believe a real computer exists at the target IP
address.
[0117] If the packet is a TCP packet as seen in a block 184, the
system may test for various types of TCP packets. For example, the
system may test to determine whether the TCP packet is a SYN
request as seen in a block 486. If it is, the system may create an
appropriate acknowledgement response as seen in a block 488. This
acknowledgement response may include the TCP window size set to
zero and the data of payload size set to a very small number as
seen in blocks 490 and 492. The TCP SYN request indicates that an
attacker may be trying to connect the first time. By sending the
suggested response, the attacker's computer is provided with
parameters requiring it to do extra work sending small packets and
effectively occupying computational cycles. If enough threads of
such TCP packets are sent out, communications to the attacker's
computer may effectively be slowed.
[0118] If the TCP packet is a window probe packet as seen in 496,
the attacker may be trying to increase the speed of their attack by
requesting a verification of a maximum window size. Here, to, an
appropriate TCP response packet may be crafted as seen in a block
498. Again, the TCP window size may be set to zero and the window
probe response packet be sent as seen in blocks 500 and 502,
respectively. If the TCP packet is an ACK packet, the attacker may
be sending the attacking packets. Typically, the attacker's
computer will wait about four minutes before being allowed to try
and send another packet. In this case, if the packet is ignored as
seen in a block 506, the attacker's efforts are effectively slowed
while his computer waits over the appropriate response period.
[0119] FIGS. 26A and 26B represent a potential defense against an
attack. In this method 510, the communications between an attacking
computer and other devices on the local network is controlled. The
system may accept a packet as seen in a block 512. The source IP
address and the target IP address may be tested to determine
whether they represent a threat as seen in blocks 514 and 520,
respectively. If they do represent a threat, the target physical
address may be tested to determine whether it is a synthetic
address as seen in a block 516. If the target physical address is
synthetic, the packet may be dropped as seen in a block 518 or
forwarded to an alternate device or appropriate network security
device such as a sacrificial computer or other defense device. The
target physical address or synthetic address may be hardware
addresses such as MAC addresses.
[0120] If the target physical address is not synthetic, then the
system may be under attack from a new source and an appropriate
control must be implemented. In this case, the IP address is tested
to determine whether the source is on the local network as seen in
a block 530. If the source is on the local network, then a single
synthetic physical address is created. The synthetic physical
address may, for example, be an address not in use on the local
segment. Then, for each local device on the local segment, the
system may create an ARP packet using the attacker's source IP
address and the synthetic physical address as the source of the ARP
packet as seen in a block 536. An example of the ARP packet is
described in relation to FIG. 19. The destination of the ARP packet
may be the IP address and physical address of the local device as
seen in a block 538. The packet may then be sent as seen in a block
540. This process is repeated for all devices on the local network.
This method effectively adjusts the ARP tables on local devices,
providing a false address for the attacker's computer.
[0121] Subsequently, for each device on a local network segment, a
unique synthetic physical address may be created in a process
similar to that seen in a block 552. An ARP packet may then be
created using the local device source IP address and the synthetic
MAC address as the source of the ARP packet. The physical address
of the threat may be set as the destination of the ARP packet
similar to that seen in a block 556. Then, the ARP packet may be
sent to the threat similar to that seen in a block 558. Again, this
process is repeated for all devices on the local network. In
effect, communications emanating from the threat entering are sent
to addresses other than those of the devices on the local network,
masking those devices.
[0122] If the source is not on the local network, then for each
device on a local network segment, a unique synthetic physical
address may be created as seen in a block 552. An ARP packet may
then be created using the local device source IP address and the
synthetic MAC address as the source of the ARP packet. The physical
address of the default gateways may be set as the destination of
the ARP packet as seen in a block 556. Then, the ARP packet may be
sent to the default gateway as seen in a block 558. Again, this
process is repeated for all devices on the local network. In
effect, communications entering the local network are sent to
addresses other than those of the devices on the local network,
masking those devices from devices external to the network.
[0123] If however, the source IP address and the target IP address
are not of interest or do not represent threats, the packet may be
tested to determine whether the target physical address is
synthetic as seen in a block 552. If the target address is
synthetic, the system may replace the synthetic address with an
appropriate real address of the target device as seen in a block
524. Subsequently, the system may send the reformulated packet as
seen in a block 526.
[0124] In performing this method, the system may maintain a listing
of synthetic hardware or physical addresses and the real hardware
or physical address on the network. When checking for a synthetic
address, the system may compare the hardware address to the list.
When seeking to reform the packet, the system may substitute the
real hardware or physical address for the synthetic address.
[0125] FIG. 27 is a schematic block diagram depicting an exemplary
embodiment of a system. In this case, a local network segment is
depicted to the right side of a router. Along the segment may be
physical devices 1 and 2, and a security device D. There may also
be various physical addresses, S1, S2 and S3 that are not in use on
the local network segment. If a threat penetrates the local network
segment as denoted by the "T" block to the right of the router,
then any communications with the threat outside the local network
segment may be effectively controlled by preventing devices 1 and 2
from communicating with the threat. In this case, the ARP tables of
these devices 1 and 2 may be adjusted such that they send their
responses to a synthetic address on the network. In this manner,
the threat inside the local network segment will never receive a
reply to any messages sent to devices 1 and 2 on the local network
segment. This disruption may be accomplished by a security device D
sending an ARP packet to devices 1 and 2 providing them with a
false physical address associated with the threat's IP address.
[0126] In another exemplary embodiment, the threat may exist
outside the local network segment as denoted by the threat block.
In this case, the threat may-be mitigated by providing a false
physical address for each device on the local network. In this
case, any communications designed to go to device 1 or 2 may be
instead be directed to a synthetic address such as S1 or S2 the
security device D may send synthetic addresses for each device 1
and 2 on the network to a gateway device. In this manner, when the
gateway device seeks to route communications from the threat
outside the local network segment to devices on the network, it
instead sends these packets to the synthetic address S1 and S2,
respectively.
[0127] Aspects of the invention may be found in a system, method,
and computer readable medium for managing logical and physical
address state lifecycles. Aspects of the invention may be found in
a system, method, and computer-readable medium for managing logical
and physical address state lifecycles. The method can include
assigning a respective state of unknown to a first address of
multiple addresses when the respective state of the first address
has not been assigned. The method further includes changing the
respective state of the first address when a communication is
targeted to the first address. The addresses can include all valid
logical addresses for a corresponding set of devices on a segment
of a network, or all valid physical addresses for a corresponding
set of devices on a segment of a network.
[0128] The respective state of the first address can be changed to
used when the communication indicates that the first address
corresponds to a device in use. The respective state of the first
address can be changed to unfulfilled when the communication
includes an address resolution protocol request sent to a device
having the first address when a time limit for a response to the
address resolution protocol request has not expired. The respective
state of the first address can be changed to omitted when the first
address corresponds to a device, and communication with the device
is omitted from being observed. In addition, the respective state
of the first address can be changed to omitted when the respective
state of the first address is programmed to be omitted from the
changing.
[0129] The respective state of the first address can be changed to
virtual when the communication is received at the first address
when the respective state of the first address is unfulfilled, and
a time limit for responding to the communication expires before a
response is sent by the first address. The respective state of the
first address can be changed to unknown when the respective state
of the first address is not unknown, and the first address does not
participate in the communication within a time limit. The
respective state of the first address can be changed to automatic
when an automatic reply is programmed to be sent to a second
address when the first address receives a packet from the second
address.
[0130] Additional aspects of the invention may be found in a system
for managing logical and physical address state lifecycles. The
system may be a computational device including a processor or
network interface and memory or computer-readable medium, among
others. The device may or may not include a user interface.
Further, the device may have various data and instructions
associated with various methods for managing logical and physical
address state lifecycles. These data may include an ARP request
queue, an IP state table, a frequency table, an ARP table, a watch
list, a threat list, a synthetic physical address table, and a
communications stream table, among others. The device may also
include packet instructions for evaluating reconnaissance rules,
behavioral rules and other rules, among others. Further, the system
may include software or computer interpretable instructions for
performing various methods associated with maintaining the data in
the tables and collecting the data for the tables.
[0131] As such, a system, method, and computer-readable medium for
managing logical and physical address state lifecycles are
described. In view of the above detailed description of the present
invention and associated drawings, other modifications and
variations will now become apparent to those skilled in the art. It
should also be apparent that such other modifications and
variations may be effected without departing from the spirit and
scope of the present invention as set forth in the claims which
follow.
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