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Resilience To Jamming Attacks

Resilience To Jamming Attacks. Rabat Anam Mahmood Department of Electrical Engineering & Computer Science rabat@ittc.ku.edu. 14 August 2008. 1. Jamming Attacks Outline. Feasibility of Launching & Detecting Jamming Attacks in Wireless Networks

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Resilience To Jamming Attacks

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  1. Resilience To Jamming Attacks Rabat Anam Mahmood Department of Electrical Engineering & Computer Science rabat@ittc.ku.edu 14 August 2008 Jamming Attacks 1

  2. Jamming Attacks Outline • Feasibility of Launching & Detecting Jamming Attacks in Wireless Networks • Adaptive Radio Channel Allocation for Supporting Coexistence of 802.15.4 & 802.11b • Defending Against Jamming Attacks in Wireless Local Area Networks • References 14 August 2008 Jamming Attacks 2

  3. Jamming Attacks Outline • Feasibility of Launching & Detecting Jamming Attacks in Wireless Networks • Adaptive Radio Channel Allocation for Supporting Coexistence of 802.15.4 & 802.11b • Defending Against Jamming Attacks in Wireless Local Area Networks • References 14 August 2008 Jamming Attacks 3

  4. Jamming Attacks Wireless Networks • Definitions and Characteristics • A jammer is an entity who is purposefully trying to interfere with the physical transmission and reception of wireless communications • A jammer continuously emits RF signals to fill a wireless channel so that legitimate traffic will be completely blocked • Common characteristics for all jamming attacks is that their communications are not compliant with MAC protocols 14 August 2008 Jamming Attacks

  5. Jamming Attacks Wireless Networks • Packet Send Ratio • The ratio of packets that are successfully sent out by a legitimate traffic source compared to the number of packets it intends to send out at the MAC layer • Reason • Channel busy • Transmission delayed • New packets dropped when buffer space is full • Packets that are too long in the buffer, timeout • N packets to send; M sent successfully • PSR = M/N 14 August 2008 Jamming Attacks

  6. Jamming Attacks Wireless Networks • Packet Delivery Ratio • The ratio of packets that are successfully delivered to a destination compared to the number of packets that have been sent out by the sender • Reason • Destination may not be able to decode a received packet due to interference 14 August 2008 Jamming Attacks

  7. Jamming Attacks Wireless Networks • Jamming Attack Models • Constant Jammer • Deceptive Jammer • Random Jammer • Reactive Jammer 14 August 2008 Jamming Attacks

  8. Jamming Attacks Wireless Networks 14 August 2008 Jamming Attacks

  9. Jamming Attacks Wireless Networks • Constant Jammer • Continuously emits a radio signal • Sends out random bits to the channel • Does not follow any MAC layer etiquette • Does not wait for the channel to become idle 14 August 2008 Jamming Attacks

  10. Jamming Attacks Wireless Networks • Deceptive Jammer • Constantly injects regular packets to the channel • Normal nodes will be deceived by the packets • Normal nodes just check the preamble and remain silent • Jammer can only send out preambles 14 August 2008 Jamming Attacks

  11. Jamming Attacks Wireless Networks • Random Jammer • Alternates between sleeping and jamming • After jamming for tj units of time, it turns off its radio and enters sleeping mode • After sleeping for ts units of time, it wakes up and resumes jamming (constant or deceptive) • tj and ts may be random or fixed intervals-energy conservation 14 August 2008 Jamming Attacks

  12. Jamming Attacks Wireless Networks • Reactive Jammer • Jammer stays quiet when the channel is idle • Jammer starts transmitting a radio signal as soon as it senses activity on the channel • Does not conserve energy because the jammer’s radio must be continuously on in order to sense the channel • However, it is harder to detect 14 August 2008 Jamming Attacks

  13. Jamming Attacks Wireless Networks • Level of Interference • Distance between jammer and nodes • Relative transmission power of the jammer and nodes • MAC protocol employed by the nodes 14 August 2008 Jamming Attacks

  14. Jamming Attacks Wireless Networks • Detecting Jamming Attacks • Signal Strength • Carrier Sensing Time • Packet Delivery Ratio 14 August 2008 Jamming Attacks 14

  15. Feasibility of Launching & Detecting Jamming Attacks in Wireless Networks Adaptive Radio Channel Allocation for Supporting Coexistence of 802.15.4 & 802.11b Defending Against Jamming Attacks in Wireless Local Area Networks References Jamming Attacks Outline 14 August 2008 Jamming Attacks 15

  16. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b • Coexistence • Ability of one system to perform a task in a given shared environment where other systems may or may not be using the same set of rules. • Solution • Multiple radio channels for the coexistence of 802.15.4 LR WPAN and 802.11b WLAN 14 August 2008 Jamming Attacks 16

  17. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b • 802.11b has a radio transmission range of 100m • 802.15.4 has a radio transmission range of 10m • Large area and long distance interference for 802.15.4 by 802.11b • Performance degradation of 802.15.4 by 92% (a study shows) 14 August 2008 Jamming Attacks 17

  18. Radio Channel Allocation Coexistence of 802.15.4 and 802.11b 14 August 2008 Jamming Attacks 18

  19. Radio Channel Allocation Coexistence of 802.15.4 and 802.11b • IEEE 802.11b has 11 channels • Each channel has a frequency range of 22 MHz • IEEE 802.15.4 has 16 channels • Each channel is 5 MHz apart • Each channel has a frequency range of 3 MHz • Frequencies of each 802.11 channel overlaps with frequency ranges for four different 802.15.4 channels • Channels 25 & 26 can be used where frequent interference of 802.11b is expected 14 August 2008 Jamming Attacks 19

  20. Radio Channel Allocation Coexistence of 802.15.4 and 802.11b 14 August 2008 Jamming Attacks 20

  21. Radio Channel Allocation Coexistence of 802.15.4 and 802.11b • Packet entering interference, at A • Radio channel switched • Switching table used • Packet leaving interference, at B • Radio channel switched again • Advantage • Small overhead for switching channels • Same routing path used 14 August 2008 Jamming Attacks

  22. Radio Channel Allocation Coexistence of 802.15.4 and 802.11b • Interference Detection • Clear channel assessment or energy detection provided as RSSI (Received Signal Strength Indicator) services in 802.15.4. • RSSI services called periodically or on demand when a sudden degradation of user throughput below a threshold is detected • If RSSI confirms that the energy level on a current channel is above the threshold, channel interference is recognized 14 August 2008 Jamming Attacks 22

  23. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b • Group Formation • Nodes broadcast Group Formation messages to the immediate neighbors • Due to interference nodes may or may not receive GF message • Nodes change the current radio channel • Border nodes provide channel conversion for the group. 14 August 2008 Jamming Attacks 23

  24. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b • Tear Down • Nodes in a group periodically check if the previous channel is clear of interference. • If so, a tear down message is sent to all the nodes in a group and the group is torn down. 14 August 2008 Jamming Attacks 24

  25. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b 14 August 2008 Jamming Attacks

  26. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b • Interference size represents the number of nodes in interference • Success rate is percentage value relative to without interference 14 August 2008 Jamming Attacks

  27. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b 14 August 2008 Jamming Attacks

  28. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b • The percentage value is the delay increase relative to the delay without interference • Since packets are routed through the interference area, the delay is not increased much 14 August 2008 Jamming Attacks

  29. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b 14 August 2008 Jamming Attacks

  30. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b • Comparison between packet delays of AODV and AODV plus (adaptive scheme) • Due to adaptive scheme, lower packet delay is attained 14 August 2008 Jamming Attacks

  31. Radio Channel AllocationCoexistence of 802.15.4 and 802.11b • Conclusion • Performance degradation by interference is mainly caused from changing routing path. • The overhead for switching radio channels is very small • Hence, by employing the adaptive scheme, routing does not need to find a new path when it hits into an interference area. 14 August 2008 Jamming Attacks 31

  32. Feasibility of Launching & Detecting Jamming Attacks in Wireless Networks Adaptive Radio Channel Allocation for Supporting Coexistence of 802.15.4 & 802.11b Defending Against Jamming Attacks in Wireless Local Area Networks References Jamming Attacks Outline 14 August 2008 Jamming Attacks 32

  33. Defend Against Jamming AttacksWireless Local Area Networks • Wireless Jamming Attacks • RTS Jamming • CTS Jamming • Solution • Cumulative-Sum-based (CUSUM) Detection Method 14 August 2008 Jamming Attacks 33

  34. Defend Against Jamming AttacksWireless Local Area Networks • RTS Jamming • Jammer occupies channel by continuously sending RTS frames with large NAV to AP • AP replies with CTS which can be heard by nearby nodes • Neighbor nodes will keep silent for a period of time indicated by NAV • Neighbor nodes can hardly occupy the channel 14 August 2008 Jamming Attacks 34

  35. Defend Against Jamming AttacksWireless Local Area Networks 14 August 2008 Jamming Attacks

  36. Defend Against Jamming AttacksWireless Local Area Networks • CTS Jamming • Jammer sends CTS frames with spoofed ID which is as same as AP • AP unaware of this behavior • Jammer uses directional antenna • Jammer remains far away from the AP • Neighbor nodes assume AP is busy (hidden node problem) and will remain silent • Neighbor nodes never get a chance to occupy the channel 14 August 2008 Jamming Attacks 36

  37. Defend Against Jamming AttacksWireless Local Area Networks 14 August 2008 Jamming Attacks 37

  38. Defend Against Jamming AttacksWireless Local Area Networks • Defending against RTS/CTS attacks • Two separate data windows for RTS & CTS • Size of the window is fixed • Source ID information of the frame is recorded • Source ID of the CTS frame is checked in the CTS window • Source ID also checked in the RTS window • Different score given to each frame using a function • Smallest index gains the highest score 14 August 2008 Jamming Attacks 38

  39. Defend Against Jamming AttacksWireless Local Area Networks • CUSUM Method • Sequential Detection Change Point method Mean value of some variable under surveillance will change from negative to positive whenever a change occurs. 14 August 2008 Jamming Attacks 39

  40. Defend Against Jamming AttacksWireless Local Area Networks • Channel is nearly fairly shared among nodes • Source ID distribution of CTS / RTS frames is uniform • If a node constantly occupies the channel, uniform distribution will change • CUSUM is applied to detect changes in CTS window • When a change point is detected, corresponding CTS frames are suspicious 14 August 2008 Jamming Attacks 40

  41. Defend Against Jamming AttacksWireless Local Area Networks 14 August 2008 Jamming Attacks

  42. Defend Against Jamming AttacksWireless Local Area Networks • Conclusion • CUSUM can accurately detect RTS/CTS jamming attacks with little computation and storage cost • Although these attacks cannot totally prevent other nodes from communication, they can seriously degrade the network throughput • These attacks have lower traffic rates than normal jamming attack and are more difficult to detect 14 August 2008 Jamming Attacks 42

  43. Feasibility of Launching & Detecting Jamming Attacks in Wireless Networks Adaptive Radio Channel Allocation for Supporting Coexistence of 802.15.4 & 802.11b Defending Against Jamming Attacks in Wireless Local Area Networks References Jamming Attacks Outline 14 August 2008 Jamming Attacks 43

  44. http://www.winlab.rutgers.edu/~trappe/Papers/JamDetect_Mobihoc.pdfhttp://www.winlab.rutgers.edu/~trappe/Papers/JamDetect_Mobihoc.pdf http://ieeexplore.ieee.org/iel5/10422/33099/01559004.pdf?arnumber=1559004 http://www.springerlink.com/content/l2qp0215r1268p4t/fulltext.pdf Jamming Attacks References 14 August 2008 Jamming Attacks 44

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