Transcript Vulnerability Analysis and Intrusion Mitigation Systems for WiMAX Networks Yan Chen, Hai Zhou

Vulnerability Analysis and
Intrusion Mitigation Systems
for WiMAX Networks
Yan Chen, Hai Zhou
Motorola Liaisons
Northwestern Lab for Internet Greg W. Cox, Z. Judy Fu,
and Security Technology (LIST) Peter McCann, and Philip R.
Roberts
Dept. of Electrical Engineering
and Computer Science
Motorola Labs
Northwestern University
http://list.cs.northwestern.edu
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
Protocol
Specification
Normal
Traffic Pool
Protocol
Parser
Parsed
Normal
LESG
Core
Signatures
Parsed
Suspicious
Suspicious
Traffic Pool
NO
Pool size
too small?
Quit
YES
Filter
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 Network
HoT
Mobile
Mobile
Node
Node
Correspondent
Node
Home Agent
HoTI
HA
BA
HoTI
–M
N
n
Tu
ne
HoT
BU
CoT
BA
l
Foreign Network
CoTI
BU
Internet
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
Action
MN
HA
AT
CN
Start
Return
Routability
Restart
Return
Routability
Silently
Discard
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)
EAP-TLS
EAP-TTLS
PEAP
EAP-SIM
EAP-AKA
Authentication
method
EAP-FAST
layer
Extensible Authentication Protocol (EAP)
EAP Layer
EAP Over LAN (EAPOL)
PPP
802.16
802.3
Ethernet
802.5
Token Ring
802.11
WLAN
GSM
CDMA
Data Link
Layer
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
802.16e SS Init Flowchart
Work Done
Future work
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
User
s
802.16
BS
802.16
BS
802.16
BS
User
s
Internet
Users
Inter
net
scan
port WAIDM
system
• 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
Switch/
BS controller
Switch/
BS controller
802.16
BS
Users
(a)
Original configuration
(b) WAIDM
deployed