U.S. patent application number 11/695569 was filed with the patent office on 2007-07-26 for automated sniffer apparatus and method for wireless local area network security.
This patent application is currently assigned to AirTight Networks, Inc.(F/K/A Wibhu Technologies, Inc.). Invention is credited to Pravin Bhagwat, Shantanu Gogate, David C. King.
Application Number | 20070171885 11/695569 |
Document ID | / |
Family ID | 36000515 |
Filed Date | 2007-07-26 |
United States Patent
Application |
20070171885 |
Kind Code |
A1 |
Bhagwat; Pravin ; et
al. |
July 26, 2007 |
AUTOMATED SNIFFER APPARATUS AND METHOD FOR WIRELESS LOCAL AREA
NETWORK SECURITY
Abstract
A method for protecting local area networks within a selected
local geographic region (e.g. office, apartment, building, coffee
shop, hot-spot etc.) from wireless attacks, using a wireless
sniffer apparatus. The method includes placing one or more wireless
sniffer apparatus spatially to provide substantial radio coverage
over at least a portion of the selected local geographic region
comprising one or more local area networks. Moreover the method
includes coupling one or more of the wireless sniffer apparatus to
one or more of the local area networks.
Inventors: |
Bhagwat; Pravin; (Kendall
Park, NJ) ; Gogate; Shantanu; (Pune, IN) ;
King; David C.; (Menlo Park, CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
AirTight Networks, Inc.(F/K/A Wibhu
Technologies, Inc.)
Mountain View
CA
|
Family ID: |
36000515 |
Appl. No.: |
11/695569 |
Filed: |
April 2, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
11123848 |
May 6, 2005 |
7216365 |
|
|
11695569 |
Apr 2, 2007 |
|
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11086266 |
Mar 21, 2005 |
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11123848 |
May 6, 2005 |
|
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10931585 |
Aug 31, 2004 |
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11086266 |
Mar 21, 2005 |
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60543631 |
Feb 11, 2004 |
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Current U.S.
Class: |
370/338 ;
713/168 |
Current CPC
Class: |
H04L 63/1475 20130101;
H04W 8/26 20130101; H04L 69/16 20130101; H04W 12/069 20210101; H04W
84/04 20130101; H04L 63/1466 20130101; H04L 63/1416 20130101; H04L
69/163 20130101; H04L 63/1408 20130101; H04L 43/00 20130101; H04W
12/122 20210101; H04W 84/12 20130101; H04L 69/161 20130101 |
Class at
Publication: |
370/338 ;
713/168 |
International
Class: |
H04Q 7/24 20060101
H04Q007/24 |
Claims
1. An apparatus for intrusion detection in wireless communication
networks, the apparatus comprising: a single housing, the housing
comprising; a processing unit; one or more wireless network
interface devices coupled to the processing unit; at least one
network interface device coupled to the processing unit, the at
least one network interface device being adapted to operably couple
the housing to a local area network to be protected from intrusion;
and one or more memories coupled to the processing unit, the one or
more memories including: one or more codes directed to perform a
process for detection of a wireless activity within a selected
local geographic region, the wireless activity being derived from
at least one authorized device or at least an other device, the
wireless activity being received using one or more of the wireless
network interface devices; one or more codes directed to receiving
at least identity information associated with the wireless activity
from the detection process in a classification process; one or more
codes directed to labeling the identity information into at least
one of a plurality of categories in the classification process, the
plurality of categories including at least authorized, unauthorized
and external; and one or more codes directed to generating
indication associated with the identity information; whereupon the
codes directed to perform the process for detection, the receiving
the identity information, the labeling the identity information and
the generating indication are all entirely executed within the
processing unit.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S.
application Ser. No. 11/123,848, (Attorney Docket Number
022384-000622US) filed on May 6, 2005; which is a
continuation-in-part to U.S. application Ser. No. 11/086,266,
(Attorney Docket Number 022384-000621US) filed on Mar. 21, 2005;
which is a continuation-in-part to U.S. application Ser. No.
10/931,585, (Attorney Docket Number 022384-000620US) filed on Aug.
31, 2004; which claims priority to U.S. Provisional Application No.
60/543,631, (Attorney Docket Number 022384-000600US) filed Feb. 11,
2004, commonly assigned, and are hereby incorporated by reference
for all purposes.
[0002] This present application is also related to U.S. application
Ser. No. 10/931,926 (Attorney Docket Number 022384-000610US) filed
on Aug. 31, 2004, commonly assigned, and hereby incorporated by
reference for all purposes; which claims priority to U.S.
Provisional Application No. 60/543,631, (Attorney Docket Number
022384-000600US) filed Feb. 11, 2004, commonly assigned, and hereby
incorporated by reference for all purposes.
BACKGROUND OF THE INVENTION
[0003] The present invention relates generally to wireless computer
networking techniques. More particularly, the invention provides a
sniffer apparatus and method for providing intrusion detection for
local area wireless networks according to a specific embodiment.
Merely by way of example, the invention has been applied to a
computer networking environment based upon the IEEE 802.11 family
of standards, commonly called "WiFi." But it would be recognized
that the invention has a much broader range of applicability. For
example, the invention can be applied to Ultra Wide Band ("UWB"),
IEEE 802.16 commonly known as "WiMAX", Bluetooth, and others.
[0004] Computer systems proliferated from academic and specialized
science applications to day to day business, commerce, information
distribution and home applications. Such systems include personal
computers, which are often called "PCs" for short, to large
mainframe and server class computers. Powerful mainframe and server
class computers run specialized applications for banks, small and
large companies, e-commerce vendors and governments. Smaller
personal computers can be found in many if not all offices, homes,
and even local coffee shops. These computers interconnect with each
other through computer communication networks based on packet
switching technology such as the Internet protocol or IP. The
computer systems located within a specific local geographic area
such as office, home or other indoor and outdoor premises
interconnect using a Local Area Network, commonly called, LAN.
Ethernet is by far the most popular networking technology for LANs.
The LANs interconnect with each other using a Wide Area Network
called "WAN" such as the famous Internet. Although much progress
occurred with computers and networking, we now face a variety of
security threats on many computing environments from the hackers
connected to the computer network. The application of wireless
communication to computer networking further accentuates these
threats.
[0005] As merely an example, the conventional LAN is usually
deployed using an Ethernet based infrastructure comprising cables,
hubs switches, and other elements. A number of connection ports
(e.g., Ethernet ports) are used to couple various computer systems
to the LAN. A user can connect to the LAN by physically attaching a
computing device such as laptop, desktop or handheld computer to
one of the connection ports using physical wires or cables. Other
computer systems such as database computers, server computers,
routers and Internet gateways also connect to the LAN to provide
specific functionalities and services. Once physically connected to
the LAN, the user often accesses a variety of services such as file
transfer, remote login, email, WWW, database access, and voice over
IP. Security of the LAN often occurs by controlling access to the
physical space where the LAN connection ports reside.
[0006] Although conventional wired networks using Ethernet
technology proliferated, wireless communication technologies are
increasing in popularity. That is, wireless communication
technologies wirelessly connect users to the computer communication
networks. A typical application of these technologies provides
wireless access to the local area network in the office, home,
public hot-spots, and other geographical locations. As merely an
example, the IEEE 802.11 family of standards, commonly called WiFi,
is the common standard for such wireless application. Among WiFi,
the 802.11b standard-based WiFi often operates at 2.4 GHz
unlicensed radio frequency spectrum and offers wireless
connectivity at speeds up to 11 Mbps. The 802.11g compliant WiFi
offers even faster connectivity at about 54 Mbps and operates at
2.4 GHz unlicensed radio frequency spectrum. The 802.11a provides
speeds up to 54 Mbps operating in the 5 GHz unlicensed radio
frequency spectrum. The WiFi enables a quick and effective way of
providing wireless extension to the existing LAN.
[0007] In order to provide wireless extension of the LAN using
WiFi, one or more WiFi access points (APs) connect to the LAN
connection ports either directly or through intermediate equipment
such as WiFi switch. A user now wirelessly connects to the LAN
using a device equipped with WiFi radio, commonly called wireless
station, that communicates with the AP. The connection is free from
cable and other physical encumbrances and allows the user to "Surf
the Web" or check e-mail in an easy and efficient manner.
Unfortunately, certain limitations still exist with WiFi. That is,
the radio waves often cannot be contained in the physical space
bounded by physical structures such as the walls of a building.
Hence, wireless signals often spill outside the area of interest.
Unauthorized users can wirelessly connect to the AP and hence gain
access to the LAN from the spillage areas such as the street,
parking lot, and neighbor's premises. Consequently, the
conventional security measure of controlling access to the physical
space where the LAN connection ports are located is now
inadequate.
[0008] In order to prevent unauthorized access to the LAN over
WiFi, the AP implements one or more of a variety of techniques. For
example, the user is required to carry out authentication handshake
with the AP (or a WiFi switch that resides between the AP and the
existing LAN) before being able to connect to the LAN. Examples of
such handshake are Wireless Equivalent Privacy (WEP) based shared
key authentication, 802.1x based port access control, 802.11i based
authentication. The AP can provide additional security measures
such as encryption, firewall. Other techniques also exist to
enhance security of the LAN over WiFi.
[0009] Despite these measures, many limitations still exist. As
merely an example, a threat of an unauthorized AP being connected
to the LAN often remains with the LANs. The unauthorized AP creates
a security vulnerability. The unauthorized AP allows wireless
intruders to connect to the LAN through itself. That is, the
intruder accesses the LAN and any proprietary information on
computers and servers on the LAN without the knowledge of the owner
of the LAN. Soft APs, ad hoc networks, and misconfigured APs
connected to the LAN also pose similar threats. As another example,
external wireless devices can launch security attacks on wireless
LAN. Such attacks include denial of service (DoS) attack, Honeypot
attack, Evil Twin attack and others. Appropriate security
mechanisms are thus needed to protect the LAN resources from
wireless intruders.
[0010] Accordingly, techniques for improving security for local
area network environments are highly desirable.
SUMMARY OF THE INVENTION
[0011] According to the present invention, techniques directed to
wireless computer networking are provided. More particularly, the
invention provides a sniffer apparatus and method for providing
intrusion detection for local area wireless networks according to a
specific embodiment. Merely by way of example, the invention has
been applied to a computer networking environment based upon the
IEEE 802.11 family of standards, commonly called "WiFi." But it
would be recognized that the invention has a much broader range of
applicability. For example, the invention can be applied to UWB,
WiMAX (802.16), Bluetooth, and others.
[0012] In a specific embodiment, the invention provides an
apparatus for intrusion detection in wireless communication
networks. The apparatus comprises a single housing (e.g. a box, an
appliance etc.). The housing comprises a processing unit (e.g. one
or more processors etc.). The housing comprises one or more
wireless network interface devices (e.g. WiFi network interface
devices) coupled to the processing unit. Moreover, the housing
comprises at least one network interface device (e.g. Ethernet
network interface device, Bluetooth network interface device, WiFi
network interface device etc.) coupled to the processing unit. The
at least one network interface device is adapted to operably couple
the housing to a local area network to be protected from intrusion.
The housing comprises one or more memories coupled to the
processing unit. The one or more memories include one or more
codes. One or more of the codes is directed to perform a process
for detection of a wireless activity within a selected local
geographic region. The wireless activity is preferably derived from
at least one authorized device or at least an other device. The
wireless activity is preferably received by the apparatus (e.g. for
the purpose of detection) using one or more of the wireless network
interface devices. One or more of the codes is directed to
receiving at least identity information (e.g. MAC address)
associated with the wireless activity from the detection process in
a classification process. One or more of the codes is directed to
labeling (e.g. automatically) the identity information into at
least one of a plurality of categories in the classification
process. In one embodiment, the plurality of categories include at
least authorized, unauthorized and external. In another embodiment,
the plurality of categories include at least authorized and
external. One or more of the codes is directed to generating
indication associated with the identity information. The codes
directed to perform the process for detection of the wireless
activity, the receiving the identity information, the labeling the
identity information and the generating indication are preferably
all entirely executed within the processing unit.
[0013] In an alternative specific embodiment, the invention
provides a method for protecting local area networks within a
selected local geographic region (e.g. office, apartment, building,
coffee shop, hot-spot etc.) from wireless attacks, using one or
more of the aforementioned apparatus (e.g. wireless sniffer
apparatus). The method includes placing one or more wireless
sniffer apparatus spatially to provide substantial radio coverage
over at least a portion of the selected local geographic region.
Preferably the selected local geographic region comprises one or
more local area networks to be protected. Moreover the method
includes coupling one or more of the wireless sniffer apparatus to
one or more of the local area networks.
[0014] Certain advantages and/or benefits may be achieved using the
present invention. In one embodiment, the invention provides for a
wireless sniffer apparatus that can protect local area networks
from wireless attacks. Advantageously, the wireless sniffer
apparatus can operate as standalone device (e.g. free from
interaction with a server device). According to specific
embodiment, the invention provides a sniffer apparatus that can be
operably coupled to local area network and thereafter protects the
local area network from unauthorized access in a standalone
fashion. In an alternative specific embodiment, the invention
provides a sniffer apparatus that can be operably coupled to local
area network and thereafter protects the local area network from
unauthorized access points that can lure authorized users into
connecting to them (e.g. to steal confidential information, cause
disruption to wireless connection etc.). In some embodiments, the
wireless sniffer apparatus can send indication associated with the
detected wireless activity to other computer systems (e.g. using
electronic mail). Depending upon the embodiment, one or more of
these benefits may be achieved. These and other benefits will be
described in more throughout the present specification and more
particularly below.
[0015] Other features and advantages of the invention will become
apparent through the following detailed description, the drawings,
and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 shows a simplified LAN architecture that supports
wireless intrusion detection according to an embodiment of the
present invention.
[0017] FIG. 1A illustrates a simplified flow diagram of an
intrusion detection method according to an embodiment of the
present invention.
[0018] FIG. 1B is a simplified illustration of a sniffer apparatus
according to an embodiment of the present invention.
[0019] FIG. 1C is a simplified flow diagram illustrating a method
for installing the sniffer apparatus according to an embodiment of
the present invention.
[0020] FIG. 2 shows a simplified logical flow of steps according to
a method of an embodiment of the present invention.
[0021] FIG. 3 shows a simplified logical flow of steps for
maintaining the list of active APs according to an embodiment of
the present invention.
[0022] FIG. 4 shows a simplified logical flow of steps in an
embodiment of the LAN connectivity test according to the present
invention.
[0023] FIG. 5 shows a simplified logical flow of steps in another
embodiment of the LAN connectivity test according to the present
invention.
[0024] FIG. 6 shows a simplified logical flow of steps in another
embodiment of the LAN connectivity test according to the present
invention.
[0025] FIG. 7 is a simplified system diagram according to an
embodiment of the present invention.
[0026] FIG. 8 is a simplified system diagram according to an
alternative embodiment of the present invention.
[0027] FIG. 9 is a simplified system diagram of a standalone
implementation according to an embodiment of the present
invention.
[0028] FIG. 10A shows a simplified system diagram of certain
conventional intrusion detection system including client-server
architecture.
[0029] FIG. 10B shows a simplified system diagram of certain
standalone intrusion detection system according to an embodiment of
the present invention.
[0030] FIG. 11A shows a simplified system diagram of certain
standalone intrusion detection system for protecting hot-spot
wireless network according to an embodiment of the present
invention.
[0031] FIG. 11B shows a simplified flowchart of method for
protecting hot-spot wireless network according to an embodiment of
the present invention.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0032] According to the present invention, techniques for wireless
computer networking are provided. More particularly, the invention
provides a sniffer apparatus and method for providing intrusion
detection for local area wireless networks according to a specific
embodiment. Merely by way of example, the invention has been
applied to a computer networking environment based upon the IEEE
802.11 family of standards, commonly called "WiFi." But it would be
recognized that the invention has a much broader range of
applicability. For example, the invention can be applied to UWB,
WiMAX (802.16), Bluetooth, and others.
[0033] FIG. 1 shows the LAN architecture that supports the
intrusion detection according to one embodiment of the invention.
This diagram is merely an example, which should not unduly limit
the scope of the claims herein. One of ordinary skill in the art
would recognize other variations, modifications, and alternatives.
As shown in FIG. 1, the core transmission infrastructure 102 for
the LAN 101 comprises of Ethernet cables, hubs and switches. Other
devices may also be included. Plurality of connection ports (e.g.,
Ethernet ports) are provided for the various computer systems to be
able to connect to the LAN. One or more end user devices 103 such
as desktop computers, notebook computers, telemetry sensors etc.
are connected to the LAN 101 via one or more connection ports 104
using wires (Ethernet cable) or other suitable devices. Other
computer systems that provide specific functionalities and services
are also connected to the LAN. For example, one or more database
computers 105 may be connected to the LAN via one or more
connection ports 108. Examples of information stored in database
computers include customer accounts, inventory, employee accounts,
financial information, etc. One or more server computers 106 may be
connected to the LAN via one or more connection ports 109. Examples
of services provided by server computers include database access,
email storage, HTTP proxy service, DHCP service, SIP service,
authentication, network management, etc. The router 107 is
connected to the LAN via connection port 110 and it acts as a
gateway between the LAN 101 and the Internet 111. The firewall/VPN
gateway 112 protects computers in the LAN against hacking attacks
from the Internet 111. It may additionally also enable remote
secure access to the LAN.
[0034] WiFi is used to provide wireless extension of the LAN. For
this, one or more authorized WiFi APs 113A, 113B are connected to
the LAN via WiFi switch 114. The WiFi switch is connected to the
LAN connection port 115. The WiFi switch enables offloading from
APs some of the complex procedures for authentication, encryption,
QoS, mobility, etc., and also provides centralized management
functionality for APs, making overall WiFi system scalable for
large scale deployments. The WiFi switch may also provide
additional functionalities such as firewall. One or more authorized
WiFi AP 116 may also be directly connected to the LAN connection
port 117. In this case AP 116 may itself perform necessary security
procedures such as authentication, encryption, firewall, etc. One
or more end user devices 118 such as desktop computers, laptop
computers, PDAs equipped with WiFi radio can now wirelessly connect
to the LAN via authorized APs 113A, 113B and 116. Although WiFi has
been provided according to the present embodiment, there can also
be other types of wireless network formats such as UWB, WiMax,
Bluetooth, and others.
[0035] One or more unauthorized APs can be connected to the LAN.
The figure shows unauthorized AP 119 connected to the LAN
connection port 120. The unauthorized AP may not employ the right
security policies. Also traffic through this AP may bypass security
policy enforcing elements such as WiFi switch 114 or firewall/VPN
gateway 112. The AP 119 thus poses a security threat as intruders
such as wireless station 126 can connect to the LAN and launch
variety of attacks through this AP. According to a specific
embodiment, the unauthorized AP can be a rogue AP, a misconfigured
AP, a soft AP, and the like. A rougue AP can be a commodity AP such
as the one available openly in the market that is brought in by the
person having physical access to the facility and connected to the
LAN via the LAN connection port without the permission of the
network administrator. A misconfigured AP can be the AP otherwise
allowed by the network administrator, but whose security parameters
are, usually inadvertently, incorrectly configured. Such an AP can
thus allow wireless intruders to connect to it. Soft AP is usually
a "WiFi" enabled computer system connected to the LAN connection
port that also functions as an AP under the control of software.
The software is either deliberately run on the computer system or
inadvertently in the form of a virus program.
[0036] The figure also shows neighbor's AP 121 whose radio coverage
spills into the area covered by LAN. The AP 121 is however not
connected to the concerned LAN 101. In one embodiment, this AP is
harmless from the intrusion standpoint. For example, this AP can be
an AP in the neighboring office, an AP is the laboratory not
connected to the concerned LAN but used for standalone development
and/or experimentation, an AP on the street providing free "WiFi"
access to passersby and other APs, which co-exist with the LAN and
share the airspace without any significant and/or harmful
interferences. In alternative embodiment, this AP 121 can be
malicious AP. For example, this AP can launch wireless attacks on
the wireless users of LAN 101. As merely an example, the AP 121 can
lure one or more of the authorized users 118 into connecting to it
(e.g. by transmitting strong radio signal, advertising the same
SSID as authorized APs, disconnecting the authorized users from
authorized APs by sending spoofed deauthentication or
disassociation message etc.). The users 118 can then unwittingly
provide confidential information (e.g. username, password etc.) to
the AP 121. As another example, the AP 121 can insert itself as
man-in-the-middle. Examples of such attacks include Honeypot AP
attack, Evil Twin attack, MonkeyJack attack, hotspotter tool
etc.
[0037] A WiFi AP delivers data packets between the wired LAN and
the wireless transmission medium. Typically, the AP performs this
function either by acting as a layer 2 bridge or as a network
address translator (NAT). The layer 2 bridge type AP simply
transmits the Ethernet packet received on its wired interface to
the wireless link after translating it to 802.11 style packet and
vice versa. The NAT AP on the other hand acts as a layer 3 (IP)
router that routes IP packets received on its wired interface to
the stations connected to its wireless interface and vice versa.
The wired side and wireless side interfaces of the NAT AP thus
usually reside on different subnets.
[0038] The intrusion detection system according to the present
invention is provided to protect the LAN 101 from unauthorized APs
and/or wireless intruders. The system involves one or more sensor
devices 122A, 122B (i.e., sniffers) placed throughout a geographic
region or a portion of geographic region including the connection
points to the LAN 101. The sniffer is able to monitor the wireless
activity in the selected geographic region. For example, the
sniffer listens to the radio channel and capture packets being
transmitted on the channel. The sniffer cycles through the radio
channels on which wireless communication can take place. On each
radio channel, it waits and listens for any ongoing transmission.
In one embodiment, the sniffer is able operate on plurality of
radio channels simultaneously. Whenever transmission is detected,
the relevant information about that transmission is collected and
recorded. This information comprises of all or a subset of
information that can be gathered from various fields in the
captured packet such as 802.11 MAC (medium access control) header,
802.2 LLC (i.e., logical link control) header, IP header, transport
protocol (e.g., TCP, UDP, HTTP, RTP etc.) headers, packet size,
packet payload and other fields. Receive signal strength (i.e.,
RSSI) may also be recorded. Other information such as the day and
the time of the day when said transmission was detected may also be
recorded.
[0039] According to a specific embodiment, the sniffer device can
be any suitable receiving/transmitting device capable of detecting
wireless activity. As merely an example, the sniffer often has a
smaller form factor. The sniffer device has a processor, a flash
memory (where the software code for sniffer functionality resides),
a RAM, two 802.11a/b/g wireless network interface cards (NICs), one
Ethernet port (with optional power over Ethernet or POE), a serial
port, a power input port, a pair of dual-band (2.4 GHz and 5 GHz)
antennas, and at least one status indicator light emitting diode.
The sniffer can be built using the hardware platform similar to one
used to built wireless access point, although functionality and
software will be different for a sniffer device. Of course, one of
ordinary skill in the art would recognize other variations,
modifications, and alternatives. Further details of the sniffers
are provided throughout the present specification and more
particularly below.
[0040] One or more sniffers 122A and 122B may also be provided with
radio transmit interface which is useful to perform intrusion
prevention procedures, i.e., to perform preventive action against
detected intrusion. In one specific embodiment, the sniffer is a
dual slot device which has two wireless NICs. These NICs can be
used in a variety of combinations, for example both for monitoring,
both form transmitting, one for monitoring and the other for
transmitting etc., under the control of software. In another
specific embodiment, the sniffer has only one wireless NIC. The
same NIC is shared in a time division multiplexed fashion to carry
out monitoring as well as defense against intrusion. The radio
transmit interface of the sniffer is also used to perform certain
other transmission procedures according to some embodiments of the
method of invention, for example transmission of market packet in
some embodiments of the LAN connectivity test, transmission of
active probe packets, and the like. Each sniffer also has Ethernet
NIC using which it is connected to the connection port 123 of the
LAN. The sniffers can be spatially disposed at appropriate
locations in the geographic area to be monitored for intrusion by
using one or more of heuristics, strategy and calculated guess.
Alternatively, a more systematic approach using an RF (radio
frequency) planning tool is used to determine physical locations
where said sniffers need to be deployed according to an alternative
embodiment of the present invention.
[0041] In a specific embodiment, the sniffer device captures
wireless activity. Such wireless activity includes, among others,
transmission of control, management or data packet between an AP
and a wireless station or among wireless stations, and
communication for establishing wireless connection between an AP
and a wireless station often called association. Depending upon the
embodiment, the invention also provides certain methods for
monitoring wireless activity in selected geographic regions.
[0042] According to a specific embodiment, the present invention
provides a method for monitoring a wireless communication space
(e.g., office space, home, apartments, government buildings,
warehouses, hot-spots, commercial facilities etc.) occupied by one
or more computer networks which may be outlined as follows. [0043]
1. Provide a geographic region; [0044] 2. Operate a local area
network in a selected portion of the geographic region; [0045] 3.
Monitor a selected local geographic region in the geographic region
using one or more sniffer devices; [0046] 4. Detect a wireless
activity from at least one authorized device, at least one
unauthorized device, or at least one external device, within the
selected local geographic region using at least one of the sniffer
devices from the one or more sniffer devices; [0047] 5. Receive at
least identity information (e.g., source information, destination
information, MAC address) associated with the wireless activity in
a classification process; [0048] 6. Label the identity information
into at least one of a plurality of categories; [0049] 7. Transfer
an indication associated with the identify information to a
prevention process; and [0050] 8. Perform other steps, as
desired.
[0051] The above sequence of steps provides methods according to an
embodiment of the present invention. As shown, the method uses a
combination of steps including a way of detecting for an intrusion
using wireless computer networks. In preferred embodiments, the
present invention also includes an automated method for
transferring an indication of an intrusion to a prevention process,
which would preferably stop the intruding device before any
security problems or the like. Many other methods and system are
also included. Of course, other alternatives can also be provided
where steps are added, one or more steps are removed, or one or
more steps are provided in a different sequence without departing
from the scope of the claims herein. Additionally, the various
methods can be implemented using a computer code or codes in
software, firmware, hardware, or any combination of these.
Depending upon the embodiment, there can be other variations,
modifications, and alternatives. Further details of the present
method can be found throughout the present specification and more
particularly below.
[0052] FIG. 1A illustrates a simplified flow diagram of an
intrusion detection method according to an embodiment of the
present invention. This diagram is merely an example, which should
not unduly limit the scope of the claims herein. One of ordinary
skill in the art would recognize other variations, modifications,
and alternatives. As shown, the present invention provides a method
for monitoring a wireless communication space (e.g., office space,
home, apartments, government buildings, warehouses, hot-spots,
commercial facilities etc.) occupied by one or more computer
networks, e.g., wired, wireless. As shown, the method includes
providing a geographic region, step 1. According to a specific
embodiment, the geographic region can be within a building, outside
of a building, or a combination of these. As an example, the region
can be provided in an office space, home, apartments, government
buildings, warehouses, hot-spots, commercial facilities, etc. The
method includes operating a local area network in a selected
portion of the geographic region. The local area network (step 2)
is commonly an Ethernet based network for private use and may be
for public use or any combination of these.
[0053] In a specific embodiment, the method monitors (step 3) a
selected local geographic region in the geographic region using one
or more sniffer devices. The method includes detecting (step 4) a
wireless activity from at least one authorized device, at least one
unauthorized device, or at least one external device, within the
selected local geographic region using at least one of the sniffer
devices from the one or more sniffer devices. Preferably, the
unauthorized device is one that is physically connected to the
network but does not belong to the network. That is, the
unauthorized device has intruded the network according to preferred
embodiments.
[0054] The method includes receiving (step 5) at least identity
information (e.g., source information, destination information, MAC
address) associated with the wireless activity in a classification
process. The method also includes labeling (step 6) the identity
information into at least one of a plurality of categories, e.g.,
authorized, not authorized, external, connected, not connected, and
any combination of these. Of course, one of ordinary skill in the
art would recognize variations, modifications, and
alternatives.
[0055] According to a specific embodiment, the method transfers
(step 7) an indication associated with the identify information to
a prevention process. As merely an example, once the unauthorized
access point has been detected, the method sends an indication of
the unauthorized access point to the prevention process.
Preferably, the indication is sent almost immediately or before the
transmission of one or few more packets by intruders, which is
virtually instantaneously. Depending upon the embodiment, the
method sends the indication via an inter process signal between
various processes, which can be provided in computer codes.
Alternatively, the method performs a selected function within the
same process code to implement the prevention process. Certain
details of the prevention process can be found throughout the
present specification and more particularly below. Depending upon
the embodiment, the method can perform other steps, as desired.
[0056] The above sequence of steps provides methods according to an
embodiment of the present invention. As shown, the method uses a
combination of steps including a way of detecting for an intrusion
using wireless computer networks. In preferred embodiments, the
present invention also includes an automated method for
transferring an indication of an intrusion to a prevention process,
which would preferably stop the intruding device before any
security problems or the like. Many other methods and system are
also included. Of course, other alternatives can also be provided
where steps are added, one or more steps are removed, or one or
more steps are provided in a different sequence without departing
from the scope of the claims herein. Additionally, the various
methods can be implemented using a computer code or codes in
software, firmware, hardware, or any combination of these.
Depending upon the embodiment, there can be other variations,
modifications, and alternatives.
[0057] FIG. 1B is a simplified illustration of a sniffer apparatus
according to an embodiment of the present invention. This diagram
is merely an illustration, which should not unduly limit the scope
of the claims herein. One of ordinary skill in the art would
recognize many variations, modifications, and alternatives. As
shown, the invention provides a wireless sniffer apparatus
including an automated intrusion detection process. The apparatus
has housing 11, which is characterized by a length no greater than
a first dimension, a width no greater than a second dimension, and
a height of no greater than a third dimension. Preferably, the
housing has a length no greater than a first dimension of about 40
centimeters, a width no greater than a second dimension of about 25
centimeters, and a height of no greater than a third dimension of
about 10 centimeters. The housing may be made of metal or plastic,
which is suitable in strength and durable. The housing encloses
circuitry including chips, memory devices, wireless and wired
network interface devices etc., which will be described in more
detail below. In an embodiment, the wireless sniffer apparatus can
be provided within an enclosure, which provides a packaging
material to protect the wireless sniffer apparatus. The wireless
sniffer apparatus can be removed from the enclosure for using
it.
[0058] In a specific embodiment, the apparatus has a processing
unit (e.g., operable at a clock speed of more than 10 MHz) within
the housing and one or more wireless network interface devices
(e.g., transmitter/receiver) within the housing and coupled to the
processing unit. In an embodiment, the processing unit comprises
one or more microprocessors. The apparatus has one or more antennas
12 coupled to the one or more wireless network interface devices.
Depending upon the embodiment, the one or more antennas are adapted
to protrude outside of a portion of the housing or be within the
housing or any combination of these. The apparatus has at least one
Ethernet network interface device (or other like device) within the
housing and coupled to the processing unit and a least one network
connector 13 (e.g., RJ-45 socket) coupled to the Ethernet network
device. One or more memories (e.g., ROM, Flash, DRAM) are coupled
to the processing unit. A code is directed to perform a process for
detection of a wireless activity within a selected local geographic
region. According to a specific embodiment, the wireless activity
is derived from at least one authorized device or at least an other
device. A code is directed to receiving at least identity
information associated with the wireless activity from the
detection process in a classification process. A code is directed
to labeling the identity information into at least one of a
plurality of categories in the classification process. The
apparatus also has a code directed to testing connectivity of at
least the other device associated with the detected wireless
activity to a local area network within the selected local
geographic region. A first output indication (e.g., light, speaker)
is on the housing. The first output indication is associated with
the authorized device. A second output indication (e.g., light,
speaker) is on the housing. Preferably, the second output
indication is associated with the other device. In a specific
preferred embodiment, the visual output indications are provided
using one or more of light emitting diodes or LEDs 14A-14E provided
on the housing. The apparatus also has serial (e.g., RS-232)
connector 15 and power input point 16. In an embodiment, an
electrical connection can be plugged into the power input point 16
to provide electrical power to the wireless sniffer apparatus.
Further details of the hardware and software functionality can be
found throughout the present specification and more particularly
below.
[0059] Preferably, the sniffer device is easy to install on a given
geographic region, as illustrated by the simplified diagram of FIG.
1C. Here, the method provides a method for installing one or more
security devices over a selected local geographic region. As shown
in step 21, the method includes providing a wireless sniffer
apparatus including an automated intrusion detection process, such
as those described herein. The method includes connecting the
network connector of the sniffer apparatus to the local area
network, step 22. The method includes executing computer codes
directed to testing connectivity of at least an other device
associated with the detected wireless activity to the local area
network as shown in step 23 and outputting either the first output
indication or the second output indication based upon the detected
wireless activity as shown in step 24. Further details of various
methods being carried out in the sniffer apparatus including a
block diagram can be found throughout the present specification and
more particularly below.
[0060] FIG. 2 shows the logical flow of steps for wireless
intrusion detection according to the method of the invention. This
diagram is merely an example, which should not unduly limit the
scope of the claims herein. One of ordinary skill in the art would
recognize other variations, modifications, and alternatives. As
shown, the first step 201 is to maintain the list of active APs
called the Active_AP_List. An active AP can be an AP that was
recently involved in the wireless transmission as the sender or the
receiver. An active AP can be detected by analyzing the wireless
transmission on the radio channel captured by the sniffer. For
example, every AP in the WiFi network periodically transmits a
beacon packet for the client wireless stations to be able to
connect to it. The beacon packet contains information such as clock
synchronization data, AP's MAC address (BSSID), supported data
rates, service set identifiers (SSIDs), parameters for the
contention and contention-free access to the wireless medium,
capabilities as regards QoS, security policy, etc. In one
embodiment, detection of beacon packet transmission from an AP is
used to identify said AP to be an active AP. Beacon packet can be
recognized from the type and subtype fields in the 802.11 MAC
header of the beacon packet. In alternate embodiments, active AP
can also be detected when any other wireless transmission (data,
control or management packet) directed to or generating from it is
observed by the sniffer. Whenever an active AP is detected, it is
added to the Active_AP_List. If the Active_AP_List already contains
entry for said AP, the corresponding entry is refreshed. Associated
with each entry in the Active_AP_List are a short timeout and a
long timeout values. After a short timeout, the corresponding entry
is marked "inactive" and after a long timeout it is marked
"historic". The logical flow of steps for maintaining the
Active_AP_List is shown in FIG. 3. This diagram is merely an
example, which should not unduly limit the scope of the claims
herein. One of ordinary skill in the art would recognize other
variations, modifications, and alternatives.
[0061] The second step 202 is to classify the APs in Active_AP_List
into at least three categories, namely "authorized", "unauthorized"
and "external". An authorized AP can be an AP which is allowed to
be connected to the LAN by network administrator. An unauthorized
AP can be an AP that is not allowed to be connected to the LAN, but
is still connected to the LAN. The unauthorized APs can pose
security threat to the LAN. An external AP can be an AP that can be
detected in the air by sniffers but is not connected to the LAN.
For example, external APs can be neighbor's APs, other extraneous
APs etc. whose radio coverage spills into the region of LAN
operation. In one embodiment, the external APs coexist with the LAN
and may not pose a security threat. In another embodiment, the
external APs are malicious APs and pose security threat to the LAN.
One or more tests are performed to classify APs in the
Active_AP_List into these categories.
[0062] The third step 203 is intrusion detection. When an
unauthorized AP is detected, intrusion alert is generated. Whenever
any wireless station attempting connection to or connected to
unauthorized AP is detected, intrusion alert is generated. Once the
intrusion alert is generated, the method sends an indication of the
AP and/or intruding wireless station to a prevention process.
Preferably, the indication is sent almost immediately or before the
transmission of one or few more packets by intruders. Depending
upon the embodiment, the method sends the indication via an inter
process signal between various processes, which can be provided in
computer codes. Alternatively, the method performs a selected
function within the same process code to implement the prevention
process. Further details of the prevention process can be found
throughout the present specification and more particularly
below.
[0063] The fourth step 204 is intrusion prevention wherein
subsequent to intrusion alert; action is taken to disable or
disrupt any communication between unauthorized AP and intruding
wireless station. One embodiment of this step works by preventing
or breaking the "association" between unauthorized AP and intruding
wireless station. Association is the procedure defined in 802.11
standard wherein the wireless station and the AP establish a
wireless connection between them. Techniques for preventing or
breaking the association include but are not limited to sending one
or more spoofed "deauthentication" packets from one or more
sniffers with AP's MAC address as source address with a reason code
"Authentication Expired" to a particular intruding wireless station
or to a broadcast address, sending one or more spoofed
De-Authentication packets from one or more sniffers to unauthorized
AP with intruding wireless station's MAC address as source address
with reason code "Auth Leave", sending one or more spoofed
"disassociation" packets from one or more sniffers with AP's MAC
address as source address to a particular intruding wireless
station or to a broadcast address and sending one or more spoofed
disassociation packets from one or more sniffers to unauthorized AP
with intruding wireless station's MAC address as source address.
Another embodiment of this step involves continuously sending
frames from one or more sniffers with BSSID field containing MAC
address of unauthorized AP and a high value in network allocation
vector (NAV) field. All client wireless stations of said AP
including said intruding wireless station then defer access to
radio channel for the duration specified in NAV field. This causes
disruption to the communication between said AP and said intruding
wireless station. A number of other embodiments such as inflicting
acknowledgement (ACK) or packet collisions via transmissions from
the sniffer, destabilizing or desynchronizing the wireless stations
within the BSS (basic service set) of unauthorized AP by sending
confusing beacon frames from the sniffer can also be used.
[0064] In the preferred embodiment of the method of invention, in
step 202 a test called the "LAN connectivity test" is used to
distinguish the APs in the Active_AP_List that are connected to the
LAN (e.g., authorized or unauthorized) from those that are not
connected to the LAN (e.g., external). The logical flow of steps
according to an embodiment of the LAN connectivity test is shown in
FIG. 4. This diagram is merely an example, which should not unduly
limit the scope of the claims herein. One of ordinary skill in the
art would recognize other variations, modifications, and
alternatives. As shown in step 401, one or more marker packets are
transmitted to the LAN by the originating device. The originating
device can be a sniffer. For example, the sniffer can transmit the
marker packet to the concerned LAN via the Ethernet port. The
marker packet has a peculiar format using which it can later be
identified by the intrusion detection system. The format can be
different for different marker packets. The marker packet may
contain a sequence number using which it can later be compared
against the known marker packets. The marker packet may contain
identity of the originating device. The marker packet is received
by all or a subset of APs connected to the concerned LAN and
transmitted by all or a subset of them on the wireless medium.
[0065] In step 402, one or more sniffers listen to one or more
radio channels on which wireless communication can take place.
[0066] In step 403, at least one sniffer detects the transmission
of at least one marker packet on the radio channel. The marker
packet is detected by analyzing the format of the captured packet.
If the AP transmits marker packet on the radio channel without
modifying it via encryption procedure all the format information in
the detected packet is available to the intrusion detection system
for analysis for identifying marker packet. If the AP transmits
marker packet on the radio channel after modifying it via
encryption procedure the intrusion detection system may not be able
to analyze all the format information in the detected packet. In
this case, certain features of the packet format that are
unaffected by encryption procedure are used for analysis. For
example, the encryption procedure does not change the size of the
data being encrypted. Thus the size of detected packets can be used
as a format parameter to identify said packet as the marker
packet.
[0067] Then in step 404 the identity of the AP that transmits the
marker packet is determined from the 802.11 MAC header (for example
from the transmitter address or BSSID fields) of the packet
transmitted on the radio channel.
[0068] In step 405, the AP that transmits the marker packet is
declared to be connected to the LAN. In a preferred embodiment, the
corresponding entry in the Active_AP_List is marked as "connected
to the LAN".
[0069] In one embodiment of the above method, the marker packet is
an Ethernet style packet addressed to the broadcast address, i.e.,
the value of hexadecimal ff:ff:ff:ff:ff:ff in the destination
address field of Ethernet MAC header. This packet will be received
by all APs that are present in the LAN broadcast domain. The APs
among these acting as layer 2 bridges then transmit this broadcast
packet on the wireless medium after translating it to the 802.11
style packet.
[0070] In alternate embodiment, the marker packet is an Ethernet
style unicast packet addressed to the MAC address of a wireless
station associated with an AP. Said MAC address is inferred by
analyzing the prior communication between said wireless station and
said AP captured by the sniffer. This packet will be received by
said AP if it is connected to the concerned LAN. Said AP acting as
layer 2 bridge then transmits the marker packet on the wireless
medium after translating it to the 802.11 style packet.
[0071] In another alternate embodiment, the marker packet is an IP
packet addressed to the IP address of a wireless station associated
with an AP. Said IP address is inferred by analyzing the prior
communication between said wireless station and said AP that is
captured by the sniffer. This packet will be received by said AP if
it is connected to the concerned LAN and transmitted by said AP on
the wireless medium after translating it to the 802.11 style
packet.
[0072] In yet an alternate embodiment, the marker packet is an IP
packet addressed to the broadcast IP address of the LAN.
[0073] In one embodiment, the marker packet is not actively
injected in the LAN by the intrusion detection system. Rather, one
or more broadcast/multicast/unicast packets from the data traffic
on the LAN are used as marker packets. The logic being if an AP is
connected to the same LAN as the sniffer, then at least the subset
of the data traffic seen by the Ethernet port of the sniffer will
be same as the data traffic captured by the sniffer on the radio
channel. Thus the sniffer compares the packet captured on the radio
channel with the packets transmitted over the wired LAN and
captured by the sniffer's LAN connection port (Ethernet NIC) to
identify a matching format.
[0074] The sniffer can detect the appearance of the marker packet
on a specific radio channel only if the sniffer is tuned to said
radio channel during the interval of transmission of the marker
packet on said radio channel. It may thus be necessary to send
marker packets in the LAN periodically and preferably at randomized
intervals, so as to maximize the probability that at least one
sniffer gets an opportunity to detect at least one marker packet
transmitted by each AP connected to the LAN. In a preferred
embodiment, a sniffer originates a marker packet and the same
sniffer monitors wireless medium to detect the transmission of the
marker packet on the wireless medium from one or more APs.
[0075] The logical flow of steps according to another embodiment of
the LAN connectivity test is shown in FIG. 5. This diagram is
merely an example, which should not unduly limit the scope of the
claims herein. One of ordinary skill in the art would recognize
other variations, modifications, and alternatives. This embodiment
is particularly useful to detect unauthorized APs that implement
NAT (i.e., network address translation) functionality unlike layer
2 bridge functionality though it is also useful for the latter. The
test is also useful to detect unauthorized layer 2 bridge type APs
(e.g., soft APs) that block forwarding of broadcast packets from
the wired LAN onto the wireless medium so as to evade detection by
previous embodiment of the LAN connectivity test.
[0076] In step 501, the sniffer is tuned to the radio channel on
which an AP operates. In step 502, the sniffer establishes wireless
connection with said AP. This typically involves listening to AP's
beacon packet and subsequently performing "association" procedure
with said AP as described in IEEE 802.11 standard. Subsequent to
association, the parameters for IP connection are assigned to the
radio interface of the sniffer. A preferred method to assign IP
connection parameters is for the sniffer to perform DHCP (i.e.,
dynamic host configuration protocol) request/response transactions
over the wireless connection established with AP. These parameters
comprise at least of the IP address for the radio interface of the
sniffer. The DHCP is described in RFC 2131 standard of the Internet
Engineering Task Force (IETF).
[0077] In an alternate embodiment, in step 502 rather than
establishing a new association with the AP, the sniffer reuses an
existing association between the AP and a wireless station
associated with the AP. For this, the sniffer detects the
parameters of an existing association between the AP and the
wireless station associated with the AP. The parameters include,
among others, the MAC address of the associated wireless station.
The sniffer may also determine the IP address and the TCP or UDP
port number of the wireless station by monitoring the packets
transmitted or received by the station.
[0078] In step 503, the sniffer sends one or more marker packets to
the AP over the wireless connection newly established or already
existing as applicable depending on the embodiment of step 502.
Preferably, the marker packet is addressed to the sniffer itself.
Various preferred embodiments for this step are now described.
[0079] In one embodiment of step 503, the marker packet is UDP
(i.e., user datagram protocol) packet. UDP is the transport layer
protocol used by computers in the IP network to exchange data. It
is described in RFC 768 standard of the IETF. In a preferred
embodiment, UDP marker packet has source IP address as the IP
address of the radio interface of the sniffer. In an alternative
embodiment wherein step 502 reuses existing association, preferably
the UDP marker packet has the source IP address and the source UDP
port number same as the corresponding values detected in the
packets transmitted by the wireless station whose association is
being reused by the sniffer. The destination IP address in the UDP
packet is the IP address of the wired (Ethernet) interface of the
sniffer.
[0080] In another embodiment of step 503, the marker packet is a
TCP (i.e., transmission control protocol) packet. The TCP is a
transport protocol described in RFC 793 standard of the IETF. It is
used by computers in IP network for reliable exchange of data. In a
preferred embodiment, TCP marker packet is TCP SYN packet. In
alternate embodiment, it can be any packet in TCP format. In a
preferred embodiment, TCP marker packet has source IP address as
the IP address of the radio interface of the sniffer. In an
alternative embodiment wherein step 502 reuses existing
association, preferably the TCP marker packet has the source IP
address and the source TCP port number same as the corresponding
values detected in the packets transmitted by the wireless station
whose association is being reused by the sniffer. The destination
IP address in the TCP packet is the IP address of the wired (e.g.,
Ethernet) interface of the sniffer.
[0081] In yet another embodiment of step 503, the marker packet is
any layer 2 style frame. In a preferred embodiment, the source
address in said layer 2 frame is the MAC address of the radio
interface of the sniffer. In an alternative embodiment wherein step
502 reuses existing association, preferably the source address in
the layer 2 frame is the MAC address of the wireless station whose
association is being reused by the sniffer. The destination address
in the layer 2 frame is the MAC address of the wired (e.g.,
Ethernet) interface of the sniffer.
[0082] In yet another embodiment of step 503, the marker packet is
addressed to the broadcast address. If the sniffer detects that the
IP address assigned to its radio interface is in the domain of
addresses assigned to the wired LAN, the marker packet can be
addressed to IP broadcast address in said domain of addresses. The
IP broadcast address is constructed by using all binary ones in the
host address part and using the network number of said wired LAN in
the network address part of the IP address. Alternatively, layer 2
format marker packet can be addressed to the MAC broadcast address,
which is hexadecimal ff:ff:ff:ff:ff:ff.
[0083] If said AP is indeed connected to the LAN, it will forward
marker packet from the wireless connection to the LAN and thus the
marker packet will be received at the sniffer in step 504.
[0084] Subsequently, said AP is declared to be connected to the LAN
in step 505. Alternatively, if the AP is not connected to the LAN,
the marker packet will not be received at the sniffer and said AP
is then declared unconnected to the LAN in step 506 according to a
specific embodiment.
[0085] The logical flow of steps according to another embodiment of
the LAN connectivity test is shown in FIG. 6. This diagram is
merely an example, which should not unduly limit the scope of the
claims herein. One of ordinary skill in the art would recognize
other variations, modifications, and alternatives.
[0086] For this, in step 601 the sniffer is tuned to a radio
channel. The sniffer listens to the radio channel to detect the
transmission of one or more "trigger" packets. In a specific
embodiment, the trigger packets indicate the current state of
ongoing communication between an AP and a wireless station. Knowing
this enables preparing and sending marker packet so that it is
almost indistinguishable from the packets constituting the ongoing
communication between the AP and the wireless station. This makes
it difficult for certain APs, for example compromised, software
controlled or non-standard, to evade detection by marker packet
test.
[0087] When the transmission of one or more trigger packets is
detected in step 602, the identity of the AP that is the source or
destination of the trigger packets is determined in step 603 from
the transmitter address or the receiver address in the 802.11 MAC
header of the trigger packets.
[0088] Depending upon the type of trigger packets an optional step
604 is performed to determine if said AP is suspected to be not
authorized (i.e. it can be unauthorized or external). For example
an AP in the Active_AP_List that has not previously responded to
any LAN connectivity test is suspected to be not authorized. Or, an
AP whose behavior (contents of beacon frame, MAC address,
authentication and encryption methods etc.) does not match the
behavior known of the authorized APs is suspected to be not
authorized.
[0089] In step 605 one or more marker packets are constructed based
on the type of trigger packets and information contained therein.
The marker packets are transmitted in the LAN in step 606. The
sniffer continues to listen to the same radio channel to detect the
transmission of at least one marker packet on the radio channel by
said AP. If the marker packet transmission is detected before a
timeout occurs, said AP is declared to be connected to the LAN.
Alternatively, the AP is declared unconnected to the LAN according
to a specific embodiment.
[0090] In one embodiment of the LAN connectivity test using trigger
packets, the trigger packets and the marker packets are
transmission TCP packets. TCP is used by computers in Internet
Protocol (IP) network for reliable exchange of data. TCP provides
acknowledgement-based data delivery wherein lost pieces of data are
recovered via retransmissions. The TCP also uses window-based
congestion control algorithm so as to dynamically adapt to the
available bandwidth between the communicating computers. A number
of desirable Internet applications such as HTTP, file transfer,
email, remote login, etc., are performed using TCP as transport
protocol.
[0091] Suppose the sniffer detects transmission of a TCP packet
from a wireless station to the AP (called uplink direction) that is
suspected to be not authorized. TCP packet is identified by
examining the header fields of detected packet transmission.
Specifically, for the TCP packet the value of "Type" field in 802.2
frame header is hexadecimal 0800 and the value of "Protocol" field
in the IP header is hexadecimal 06. Then the marker packet is
constructed as a TCP packet and in one embodiment the various
fields in the marker packet (step 605 above) are set as
follows:
[0092] Swap the source and destination addresses in the Ethernet,
IP and TCP headers of trigger packet to get source and destination
addresses in the corresponding headers of marker packet.
[0093] Set the TCP payload in marker packet such that it can later
be identified by the intrusion detection. Let L denote the size of
payload in number of octets.
[0094] Let x1 denote the value of "sequence number" field in the
TCP header of trigger packet and x2 denote the number of octets of
TCP payload in the trigger packet. Then set "acknowledgement
number" field in the TCP header of marker packet equal to
(x1+x2).
[0095] Let x3 denote the value of "acknowledgement number" field
and x4 denote the value of "window" field in the TCP header of
trigger packet. Then set the value of "sequence number" field in
the TCP header of marker packet to a value that is between (x3-1)
and (x3+x4-L).
[0096] Other fields in the marker packet are set according to
standard practice used by various implementations of corresponding
protocols. Among these, values for some of the fields can be more
judiciously chosen if the sniffer has also recently captured a TCP
packet of the same flow transmitted by said AP to said wireless
station (downlink). For example, the value of "window" field in the
marker packet can be set equal to or close to the value of "window"
field in the recently captured downlink TCP packet. Similarly, the
value of "Identification" field in the IP header of marker packet
can be set greater than the value of "Identification" field in the
recently captured downlink TCP packet.
[0097] Suppose that the sniffer detects downlink TCP packet. Then
the marker packet is constructed as a TCP packet and in one
embodiment the various fields in the marker packet (step 605 above)
are set as follows:
[0098] a. Swap source and destination addresses in the Ethernet, IP
and TCP headers of trigger packet to get source and destination
addresses in the corresponding headers of marker packet.
[0099] b. Set the TCP payload in marker packet such that it can
later be identified by the intrusion detection. Let L denote the
size of payload in number of octets.
[0100] c. Let x1 denote the value of "sequence number" field in the
TCP header of trigger packet and x2 denote the number of octets of
TCP payload in the trigger packet. Then set sequence number field
in the TCP header of marker packet to a value greater than
(x1+x2-1). If the sniffer has recently captured uplink TCP packet
of the same flow and thus the intrusion detection has the knowledge
of value of "window" field in recent uplink packet, the value of
"sequence number" field in marker packet should be chosen so that
it is also less than (x1+window-L+1).
[0101] d. Other fields in the marker packet are set according to
standard practice used by various implementations of corresponding
protocols. Among these, values for some of the fields such as
"window" field in TCP header and "Identification field in IP header
can be more judiciously chosen if the sniffer has also recently
captured uplink TCP packet of the same flow.
[0102] In another embodiment of the LAN connectivity test using
trigger packets, the trigger packet is DHCP request packet and the
marker packet is DHCP response packet.
[0103] In the preferred embodiment of the method of invention, in
step 202 one or more feature criteria are used distinguish the APs
in the Active_AP_List that are authorized by the network
administrator from those that are not authorized. The latter
include unauthorized and external APs. The method of invention
works by inferring one or more features of an AP via analysis of
the packets captured by the sniffer and comparing them with the
features of the authorized APs. If the discrepancy is detected,
said AP is deemed to be not authorized.
[0104] A number of features of an AP can be inferred by analyzing
one or more beacon packets transmitted by the AP. These features
include but not limited to the vendor information (indicated by the
first three bytes of the MAC address of the AP), the observed
beacon interval and values of various fields (according to basic
802.11 and its enhancements including 802.11e, 802.11i, 802.11k and
others) in the beacon packet such as beacon interval, SSID,
capabilities information, radio parameters, various information
elements (IEs) etc.
[0105] Some other features of an AP can be inferred by analyzing
the sequence of packets flowing between the AP and a wireless
station. Most notably, the flow of authentication and association
procedure (WEP, WPA, TKIP, RSN etc.) can be monitored by the
sniffer to determine if it is consistent with that of an authorized
AP.
[0106] The feature set of authorized APs can be provided to the
intrusion detection system by the network administrator.
Alternatively, the intrusion detection system can learn the
authorized feature set by detecting APs and their associated
feature set in the operational network or laboratory environment.
In the former case, the network administrator merely indicates to
the intrusion detection system as to which of the detected APs are
authorized APs.
[0107] The sniffer may perform active probing to infer the features
of an AP. For example, the sniffer attempts to establish a wireless
connection with the AP which typically involves authentication and
association procedure. The sniffer is provided with the credentials
to be used during the authentication procedure. For example, the
credentials include but not limited to password, digital
certificate, security key, etc. If the sniffer succeeds in
establishing the wireless connection with the AP, the AP may be
declared as authorized. This test is even more effective for the
authentication schemes, such as extensible authentication protocol
transport layer security (EAP TLS), which perform mutual
authentication. Depending upon the embodiment, the present
invention can implement the various methods using certain systems,
which are described in more detail below.
[0108] One embodiment of the intrusion detection system according
to present invention is described with reference to FIG. 7. The
system comprises a detection module 702, a classification module
704 and a prevention module 706, each of the modules comprising one
or more computer executable codes. The various codes can be running
in one or more computer processes.
[0109] The detection module 702 is directed to performing tasks
associated with detecting wireless activity. In a specific
embodiment the detecting comprises capturing, decoding and
processing the wireless activity. The detecting may further
comprise filtering and summarizing the information associated with
or derived from the wireless activity. The detection module is
further directed to transferring at least identity information
associated with the detected wireless activity to the
classification module. In a specific embodiment the detection
module transfers additional information associated with the
detected activity such as information derived from beacon packet,
marker packet, authentication packet and other packets to the
classification module. The classification module 704 is directed to
performing tasks associated with receiving and labeling the
identity information associated with the wireless activity into at
least one of a plurality of categories. In a specific embodiment,
the classification module analyzes the additional information
associated with the wireless activity received from the detection
module for the sake of labeling the identity information. The
classification module is further directed to performing tasks
associated with transferring indication associated with the
identity information to the prevention module 706. In one specific
embodiment, the indication is an intrusion alert. In a specific
embodiment, intrusion alert is generated when an unauthorized AP
and/or intruding wireless station is detected by the classification
process.
[0110] Another embodiment of the intrusion prevention system
according to present invention is described with reference to FIG.
8. The system comprises a providing module 801, a transferring
module 802, an outputting module 803, a receiving module 804, a
processing module 805 and an identifying module 806. Each of the
modules comprises one or more computer executable codes. The
providing module 801 prepares the marker packet with a given
format. In a specific embodiment, the providing module resides
within the originating device (e.g., sniffer). The transferring
module 802 transmits the marker packet to one or more APs over the
LAN. In a specific embodiment the transferring module resides
within the originating device (e.g., sniffer). The outputting
module 803 transmits the marker packet from the AP to the wireless
medium. In a specific embodiment, the outputting module resides
within the AP. The receiving module 804 is directed to receiving
wireless activity associated with the marker packet using at least
one sniffer. The processing module 805 is directed to processing
the wireless activity information to identify the marker packet. In
a specific embodiment, the processing module analyzes the format
information in the received wireless activity to identify the
marker packet. The identifying module 806 is directed to
determining the identity information associated with the wireless
activity associated with the marker packet. In a specific
embodiment, the identifying module determines the source AP of the
wireless activity associated with the marker packet. In another
specific embodiment, the receiving module, the processing module
and the identifying module are provided within the sniffer
device.
[0111] Another alternative embodiment of the intrusion detection
system is described below with reference to FIG. 9. In this
embodiment, the detection, classification and prevention modules
are provided within the sniffer device. The sniffer also provides
and transfers a maker packet. The sniffer further receives the
wireless activity associated with the marker packet, processes said
activity to identify the marker packet and identifies the AP that
transmits marker packet on the wireless medium. This embodiment in
particularly advantageous because it allows deployment of
standalone sniffer devices (e.g., as appliances).
[0112] Accordingly, the sniffer appliance device comprises a CPU
901 adapted to executing computer codes and a memory 902 that
stores computer codes and data. The computer codes stored in the
memory comprise at least the codes for detection, classification
and prevention modules and the codes adapted to perform
communication between said modules. The computer codes stored in
the memory further comprise the codes for providing a marker
packet, transferring a marker packet, receiving a wireless activity
associated with the marker packet, processing said wireless
activity to identify the marker packet and identifying the AP that
transmits the marker packet on the wireless medium. The sniffer
appliance device comprises one or more WiFi NICs 903 connected to
one or more antennas 904. The WiFi NICs performs the tasks
associated with receiving the wireless activity (e.g., listening to
and capturing the packet transmissions occurring over the wireless
medium in accordance with 802.11 standard) as well as initiating
the wireless activity (e.g., transmitting packets in accordance
with 802.11 standard). The Ethernet NIC 905 is also provided that
enables connecting the sniffer appliance device to the LAN via
Ethernet jack 06 (e.g., RJ-45 socket). The Ethernet jack 906 may
alternatively and additionally be used to connect the sniffer
appliance to a PC for configuration purposes. Alternatively, a
serial communication interface (e.g., RS-232) 912 is used to
connect the sniffer appliance to a PC for configuration purposes.
The various electronic components are connected together using data
transfer bus 907. The sniffer device can provide visual indication
about detected wireless activity by means of one or more light
bulbs or light emitting diodes 908 provided on the device panel
910. Optionally or in addition to, an electronic screen such as for
example LCD screen 909 is provided on the device panel for
providing visual indication and/or textual messages. In a specific
preferred embodiment, the indication is associated with a device
type selected from, but not limited to, a no active device type, at
least one active device type, all authorized device type, at least
one unauthorized device type, and at least one unauthorized device
in active communication type.
[0113] After the sniffer device is powered on, the light bulb 908
turns white in color if Active_AP_List is empty. The bulb turns
yellow when at least one active AP is detected. After the sensor
device is connected to the wired LAN (e.g., using Ethernet jack
906), it can start executing steps 202 and beyond shown in FIG. 2
according to the specific embodiment of the method of invention. If
only authorized APs connected to the LAN are detected, the bulb
turns green. If the unauthorized AP is detected in step 202, the
light bulb turns red in color. If the wireless station attempting
to connect or connected to the unauthorized AP is detected in step
203, the light bulb turns flashing red. Alternatively, the various
visual indications are provided via combination of light bulbs from
a plurality of light bulbs provided on the device panel (e.g., one
for each event). Other indications may also be provided via one or
more light bulbs. Yet alternately, such indications can also be
given in audio form, for example via different types of alarm
sounds from the speaker (not shown in FIG. 9). An on/off switch 911
may be provided on the sniffer device panel that enables turning
the intrusion defense step 204 on or off. Alternatively, the on/off
switch for activating and deactivating the intrusion defense is
software controlled. Yet alternatively, the step 204 is executed
automatically after intrusion detection.
[0114] FIG. 10A shows a simplified system diagram of certain
conventional intrusion detection system including client-server
architecture, and FIG. 10B shows a simplified system diagram of
certain standalone intrusion detection system according to an
embodiment of the present invention. This diagram is merely an
example, which should not unduly limit the scope of the claims
herein. One of ordinary skill in the art would recognize other
variations, modifications, and alternatives. As shown, a selected
local geographic region 1001 (e.g. office, building, apartment
etc.) comprises one or more segments of local area network (LAN)
1002. Plurality of computer systems, for example, a PC 1003A, an
application server 1003B (e.g. email server), a wireless AP 1003C
and a wireless laptop 1003D, are coupled to the LAN 1002.
[0115] As shown in FIG. 11A, certain conventional intrusion
detection system comprises one or more sniffer devices 1004A, 1004B
coupled to the LAN 1002 and a server device 1005 coupled to the LAN
1002. Depending upon the embodiment, the server device can be a
dedicated server appliance or it can be a general purpose computer
which runs software process directed to perform server
functionality. In a specific embodiment, the sniffer devices 1004A
and 1004B interact with the server device 1005 to perform intrusion
detection, prevention and like. Each of the sniffer devices 1004A
and 1004B have a radio coverage 1006A and 1006B respectively
associated with it. Preferably, the sniffer device can detect
wireless activity within its radio coverage.
[0116] As shown in FIG. 10B, the standalone intrusion detection
system according to present invention comprises one or more
wireless sniffer devices 1007A, 1007B coupled to the LAN 1002.
Preferably, the system is free from a server device (e.g. such as
1005). Each of the sniffer devices 1007A and 1007B have a radio
coverage 1008A and 1008B respectively associated with it.
Preferably, the sniffer device can detect wireless activity within
its radio coverage. As merely an example, each of the sniffer
devices 1007A and 1007B can send email notifications to a PC 1003A
or to an email server (e.g. 1003B).
[0117] FIG. 11A shows a simplified system diagram of certain
standalone intrusion detection system for protecting hot-spot
wireless network according to an embodiment of the present
invention. This diagram is merely an example, which should not
unduly limit the scope of the claims herein. One of ordinary skill
in the art would recognize other variations, modifications, and
alternatives. As shown, a hot-spot region 1101 (e.g. airport,
coffee shop, mall etc.) comprises wireless LAN to provide wireless
Internet access to mobile users who visit the hot-spot region. The
wireless LAN comprises a wired portion 1102 to which one or more
authorized APs 1103 are connected. Mobile user such as laptop 1104
can connect to the authorized AP 1103 and access the Internet
through it. A malicious AP 1106 can launch wireless attacks on the
wireless LAN. As merely an example, the AP 1106 can advertise the
same SSID (service set identifier) as that of the authorized AP
1103 and thus lure the laptop 1104 into wirelessly connecting to
it. The AP 1106 can then display a login and password page on the
laptop through this wireless connection. The user of laptop 1104
can unwittingly type in login and password on the displayed page,
thereby disclosing this information to the AP 1106. As another
example, the AP 1106 can insert itself as man-in-the-middle after
the laptop 1104 wirelessly connects to it. Many such attacks
including Honeypot AP attack, Evil Twin attack, AirJack attack,
hotspooter tool attack can be launched using the AP 1106.
[0118] One or more sniffer devices 1105 can be connected to the
wired portion 1102 in order to protect the wireless LAN within the
hot-spot from these and other wireless attacks. FIG. 11B shows a
simplified flowchart of method for protecting hot-spot wireless
network according to an embodiment of the present invention. This
diagram is merely an example, which should not unduly limit the
scope of the claims herein. One of ordinary skill in the art would
recognize other variations, modifications, and alternatives.
[0119] As shown, step 1111 can provide one or more sniffer devices.
Step 1112 can provide configuration data to sniffer devices. In one
embodiment, the configuration data includes email address or
Internet address of intended recipient of indications sent from the
sniffer device. In another embodiment, the configuration data
includes identity information associated with the authorized APs
1103. For example, the identity information comprises SSID
information. As another example, the identity information comprises
MAC addresses of authorized APs 1103. In one embodiment, the
configuration data is provided to the sniffer device by coupling
the device to computer system (e.g. using serial cable, Ethernet
cable or over one or more computer networks).
[0120] Step 1113 comprises connecting at least one of the sniffers
to the wired portion 1102 of the wireless LAN. Step 1114 comprises
detecting wireless activity (e.g. within and in the vicinity of
hot-spot region 1101) using the sniffers. For example, the presence
of APs 1103 and AP 1106 can be detected by the sniffer device 1105
by detecting the beacon frames or probe response frames transmitted
from these APs over the wireless medium.
[0121] Step 1115 comprises automatically classifying identity
information associated with the detected wireless activity. For
example, the AP 1106 can be categorized by the sniffer device as
external after performing the LAN connectivity test. The APs 1103
can be categorized as authorized.
[0122] Step 1116 can send indication associated the identify
information. In one embodiment, the sniffer device can determine
that the AP 1106 is not connected to the wired portion 1102 (i.e.
external), still advertises the same SSID as APs 1103. The sniffer
device can thus infer that the AP 1106 is malicious and send
indication including MAC address of the AP 1106 to a prevention
process. In another embodiment, the sniffer device can send
indication to an email address or an Internet address.
[0123] The above methods and systems are provided according to
embodiments of the present invention. As shown, the method uses a
combination of steps including a way of detecting for an intrusion
using wireless computer networks using a sniffer apparatus. In
preferred embodiments, the present invention also includes an
apparatus having an automated method for transferring an indication
of an intrusion to a prevention process, which would preferably
stop the intruding device before any security problems or the like.
Many other methods and system are also included. Of course, other
alternatives can also be provided where steps are added, one or
more steps are removed, or one or more steps are provided in a
different sequence without departing from the scope of the claims
herein. Additionally, the various methods can be implemented using
a computer code or codes in software, firmware, hardware, or any
combination of these. Depending upon the embodiment, there can be
other variations, modifications, and alternatives.
[0124] It is also understood that the examples and embodiments
described herein are for illustrative purposes only and that
various modifications or changes in light thereof will be suggested
to persons skilled in the art and are to be included within the
spirit and purview of this application and scope of the appended
claims.
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