yan chen, hai zhou northwestern lab for internet and security technology (list) dept. of electrical...
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Yan Chen, Hai ZhouNorthwestern Lab for Internet
and Security Technology (LIST)
Dept. of Electrical Engineering and Computer Science
Northwestern University
http://list.cs.northwestern.edu
Vulnerability Analysis and Intrusion Mitigation Systems for WiMAX
Networks Motorola Liaisons
Greg W. Cox, Z. Judy Fu, Peter McCann, and Philip
R. Roberts
Motorola Labs
The Current Threat Landscape and Countermeasures of WiMAX
Networks • WiMAX: next wireless phenomenon
– Predicted multi-billion dollar industry
• WiMAX faces both Internet attacks and wireless network attacks– E.g., 6 new viruses, including Cabir and Skulls, with
30 variants targeting mobile devices
• Goal of this project: secure WiMAX networks• Big security risks for WiMAX networks
– No formal analysis about WiMAX security vulnerabilities
– No intrusion detection/mitigation product/research tailored towards WiMAX networks
Our Approach
• Vulnerability analysis of 802.16e specs and WiMAX standards– Intelligent and complete checking through combo of
manual analysis + auto search through formal methods
– First, manual analysis provide hints and right level of abstraction for auto search
– Then specify the specs and potential capabilities of attackers in a formal language TLA+ (the Temporal Logic of Actions)
– Then model check for any possible attacks
• Adaptive Intrusion Detection and Mitigation for WiMAX Networks (WAIDM) – Could be differentiator for Motorola’s 802.16 products
Outline• Threat landscape and motivation• Our approach• Accomplishment of this year• Achievement highlight: a Mobile IPv6
vulnerability• Plan for the next year
Accomplishments This Year (I)• Most achieved with close interaction with
Motorola liaisons• Intelligent vulnerability analysis of WiMAX
– Focused on outsider attacks, i.e., w/ unprotected msgs
– Checked the complete spec of 802.16e before authentication
» Found some vulnerability, e.g., for ranging (but needs to change MAC)
» Published a joint paper with Motorola Labs
“Automatic Vulnerability Checking of IEEE 802.16 WiMAX Protocols through TLA+”, in Proc. of the Second Workshop on Secure Network Protocols (NPSec), 2006.
– Checked the mobile IPv4/v6» Find an easy attack to disable the route optimization of
MIPv6 !
Accomplishments This Year (II)• Automatic polymorphic worm signature
generation systems for high-speed networks– Fast, noise tolerant w/ proved attack resilience– Resulted a joint paper submission with Motorola Labs
“Network-based and Attack-resilient Length Signature Generation for Zero-day Polymorphic Worms”, submitted to IEEE International Conference on Network Protocols (ICNP) 2007.
– Patent under review by the patent committee of Motorola
Automatic Length Based Worm Signature Generation
• Majority of worms exploit buffer overflow vulnerabilities
• Worm packets have a particular field longer than normal
• Length signature generation– Parse the traffic to different fields– Find abnormally long field– Apply a three-step algorithm to determine a
length signature– Length based signature is hard to evade if the
attacker has to overflow the buffer.
Length Based Signature Generator
Filter
SuspiciousTraffic Pool
NormalTraffic Pool
YESQuit
SignaturesLESGCore
ProtocolSpecification
ParsedNormal
ParsedSuspicious
ProtocolParser
NO
Pool sizetoo small?
Evaluation of Signature Quality
• Seven polymorphic worms based on real-world vulnerabilities and exploits from securityfocus.com
• Real traffic collected at two gigabit links of a campus edge routers in 2006 (40GB for evaluation)
• Another 123GB SPAM dataset
Accomplishments on Publications
• Four conference papers and one tech report– “Detecting Stealthy Spreaders Using Online
Outdegree Histograms”, in the Proc. of the 15th IEEE International Workshop on Quality of Service (IWQoS), 2007 (26.6%).
– “A Suite of Schemes for User-level Network Diagnosis without Infrastructure”, in the Proc. of IEEE INFOCOM, 2007 (18%).
– “Towards Scalable and Robust Distributed Intrusion Alert Fusion with Good Load Balancing”, in Proc. of ACM SIGCOMM Workshop on Large-Scale Attack Defense 2006(33%).
– Automatic Vulnerability Checking of IEEE 802.16 WiMAX Protocols through TLA+, in Proc. of the Second Workshop on Secure Network Protocols (NPSec) (33%).
– Abstraction Techniques for Model-Checking Parameterized Systems, EECS Tech. Report, 2007.
Students Involved
• PhD students: – Zhichun Li, Yao Zhao (all in their 3rd years)– Lanjia Wang, Yanmei Zhang (visiting PhD
students)– Nicos Liveris (4th year)
• MS students: – Prasad Narayana (graduated) – Sagar Vemuri (1st year)
Outline• Threat Landscape and Motivation• Our approach• Accomplishment• Achievement highlight: a Mobile IPv6
vulnerability• Plan for the next year
Mobile IPv6 (RFC 3775)
• Provides mobility at IP Layer
• Enables IP-based communication to continue even when the host moves from one network to another
• Host movement is completely transparent to Layer 4 and above
Mobile IPv6 - Entities
• Mobile Node (MN) – Any IP host which is mobile
• Correspondent Node (CN) – Any IP host communicating with the MN
• Home Agent (HA) – A host/router in the Home network which:– Is always aware of MN’s current location– Forwards any packet destined to MN– Assists MN to optimize its route to CN
Mobile IPv6 - Process
• (Initially) MN is in home network and connected to CN
• MN moves to a foreign network:– Registers new address with HA by sending Binding
Update (BU) and receiving Binding Ack (BA)– Performs Return Routability to optimize route to CN
by sending HoTI, CoTI and receiving HoT, CoT– Registers with CN using BU and BA
Mobile IPv6 in Action
Home AgentCorrespondent
Node
Home Network
Foreign Network
InternetMobile Node
Mobile Node
HA
– MN
TunnelBU
BAHoTI
HoTI
CoTI
HoT
HoT
CoT
BU
BA
Mobile IPv6 Vulnerability
• Nullifies the effect of Return Routability• BA with status codes 136, 137 and 138
unprotected• Man-in-the-middle attack
– Sniffs BU to CN– Injects BA to MN with one of status codes above
• MN either retries RR or gives up route optimization and goes through HA
MIPv6 Attack In ActionMN HA AT CN
HoTI
HoTI
CoTI
CoT
HoTHoT
Start Return
Routability
Restart Return
Routability
Silently Discard
Bind Ack
Bind Update (Sniffed by AT along the way)
Bind Ack Spoofed by AT
Bind Ack
• Only need a wireless network sniffer and a spoofed wired machine (No MAC needs to be changed !)
• Bind ACK often skipped by CN
MIPv6 Vulnerability - Effects
• Performance degradation by forcing communication through sub-optimal routes
• Possible overloading of HA and Home Link• DoS attack, when MN repeatedly tried to
complete the return routability procedure • Attack can be launched to a large number of
machines in their foreign network– Small overhead for continuously sending spoofed
Bind ACK to different machines
TLA Analysis and Experiments
• With the spec modeled in TLA, the TLC search gives two other similar attacks w/ the same vulnerability– Complete the search of vulnerabilities w/
unprotected messages
• Implemented and tested in our lab– Using Mobile IPv6 Implementation for Linux (MIPL)– Tunnel IPv6 through IPv4 with Generic Routing
Encapsulation (GRE) by Cisco– When attack in action, MN repeatedly tried to
complete the return routability procedure – DOS attack !
Outline• Threat landscape and motivation• Our approach• Accomplishment• Achievement highlight: a Mobile IPv6
vulnerability• Plan for the next year
– Vulnerability analysis of EAP protocols– Insider attack analysis– Technology transfer
Extensible Authentication Protocols (EAP)
PPP802.3
Ethernet
802.5
Token Ring
802.11
WLAN802.16
EAP-FASTEAP-TTLS EAP-SIM EAP-AKAEAP-TLS
EAP Over LAN (EAPOL)
Extensible Authentication Protocol (EAP)
EAP Layer
Data Link Layer
Authentication method layer
GSM CDMA
PEAP
Extensible Authentication Protocols (EAP)
• EAP is an authenticaiton framework– Support about 40 different EAP methods
• Current targets– EAP-SIM for GSM cellular networks– EAP-AKA for 3G networks, such as UMTS and
CDMA2000– EAP-FAST (Flexible Authentication via Secure
Tunneling)»Most Comprehensive and secure EAP method
for WLAN»Will compare it w/ EAP-SIM and EAP-AKA
Insider Attack Analysis • Not hard to become a subscriber• Can five subscribers bring down an entire
WiMAX network ?• Check vulnerability after authentication
• Plan to analyze various layers of WiMAX networks– IEEE 802.16e: MAC layer– Mobile IP v4/6: network layer– EAP layer
Conclusions
• Vulnerability analysis of WiMAX protocols: 802.16e and mobile IP specs
• Adaptive Intrusion Detection and Mitigation for WiMAX Networks (WAIDM)
Thank You !
Existing WLAN Security Technology Insufficient for
WiMAX Networks • Cryptography and authentication cannot prevent
attacks from penetrating WiMAX networks– Viruses, worms, DoS attacks, etc.
• 802.16 IDS development can potentially lead to critical gain in market share– All major WLAN vendors integrated IDS into products
• Limitations of existing IDSes (including WIDS)– Mostly host-based, and not scalable to high-speed
networks– Mostly simple signature based, cannot deal with
unknown attacks, polymorphic worms– Mostly ignore dynamics and mobility of wireless
networks
Deployment of WAIDM
• Attached to a switch connecting BS as a black box• Enable the early detection and mitigation of global
scale attacks• Could be differentiator for Motorola’s 802.16 products
Original configuration WAIDM deployed
Internet
802.16BS
Users
(a)
(b)
802.16BS
Users
Switch/BS controller
Internet
sca
n
po
rtW
AID
Msy
ste
m
802.16BS
Users
802.16BS
Users
Switch/BS controller