Overcoming Jamming Style DoS Attacks On Wireless Sensor Networks

1
Overcoming Jamming Style DoS Attacks On
WirelessSensor Networks

• Presented by Nelson Moniz
• Supervisor Natalija Vlajic

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What is a Jamming DoS Attack?

• Jamming style Denial of Service (DoS) attack
  focuses on preventing networked nodes from
  communicating

• Jammer an entity who is purposefully trying to
  interfere with the physical transmission and
  reception of wireless communications

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What is a Jamming DoS Attack?

• Traditional DoS Attacks
• Attempts to fill buffer in a network device or an
  application program
• Jamming Sytle DoS
• Physical Layer Jamming
• Constant jamming of airways
• Link Layer Jamming
• Ignoring MAC etiquette

4
Methods of Jamming

• 4 Types of Jamming
• Constant Jammer
• Continuously sends random bits of data onto
  channel
• Deceptive Jammer
• Continuously sends valid packets onto the channel
• Random Jammer
• Alternates between sleeping and jamming the
  channel
• Reactive Jammer
• Attacks only when another radio is attempting to
  use the channel

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Problem Definition

• Identifying an Attack is being performed
• Determine what type of jamming attack is being
  performed
• Could the network be experiencing node failure or
  congestion?
• Overcoming the Attack
• Network of nodes must perform some sort of method
  to overcome the effects of the attack.

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Determine if Network is Under Attack

• Link Layer attack detection
• Creates a threshold denoting the amount of time a
  node should have to wait for a channel to become
  free (carrier sensing time)
• Ex) nodes should not have to wait more than 60ms
  for channel to become free
• A threshold can be determined either
  statistically or theoretically

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Determine if Network is Under Attack (cont)

• Physical Layer attack detection
• Detect the ambient noise of the environment
  during normal operation
• Sample noise levels prior to DoS attack
  commencing (i.e. when nodes are first deployed)
• If noise levels are above detected threshold
  value assume DoS attack

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Determine if Network is Under Attack (cont)

• Use signal strength and Packet Delivery Ratio
  (PDR) to detect physical layer jamming.
• PDR Ratio of packets that are successfully
  delivered to a destination compared to the number
  of packets that have been sent out by the sender
• Combinations of signal strength and PDR allow a
  node to determine if it is being jammed or if
  neighbor is experiencing a fault

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Overcoming an Attack

• Channel Surfing
• To avoid attack switch communication
  frequencies
• Problems
• In sensor networks nodes commonly only have 1
  single communication frequency
• Messages are flooded across the network to inform
  nodes of the channel change

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Overcoming an Attack (cont)

• Spatial Retreat
• Physically have the node move out of the
  effectively jammed area
• Problems
• Ability to move nodes can be costly
• Moving nodes can possibly break communication
  with neighboring nodes
• Global repositioning scheme may be difficult
  (redefine position of all nodes to avoid the DoS
  attack)

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Overcoming an Attack (cont)

• Mapping Jammed Region
• Nodes form a jammed region where packets are
  routed around that area allowing un-jammed area
  to continue to function
• Following the attack jammed region is removed and
  routing between nodes returns back to normal

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Overcoming an Attack (cont)

• Worm Holes
• Derived from Worm Hole DoS attack
• Attacking node in one area of the network
  forwards packets to a different attacking node in
  another part of the network causes nodes to
  believe they are located beside each other
• Use same idea to overcome jamming attack

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Overcoming an Attack (cont)

• Worm Holes (cont)
• Worm holes can be created by
• Physically wiring two nodes together
• Frequency hopping radios to overcome jamming
  (requires synchronization)
• Channel hopping (no synchronization)
• If jamming occurs jammed node sends information
  along worm hole to unaffected area

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Future Work

• Improved detection methods including methods to
  detect specific types of jamming.
• Solutions to jamming DoS currently focus on
  coping with the jammer (usually by allowing a
  portion of the nodes to become inoperable). Find
  a solution that will by pass the effects of the
  jammer completely.

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Questions?

• References
• 1 N. Ahmed, S.Kanhere, S. Jha, The Holes
  Problem in Wireless Sensor Networks A Survey,
  Mobile Computing and Communications Review ACM,
  vol. 9, no. 2, 2005
• 2M. Cagalj, S. Capkun, J.P. Hubaux,
  Wormhole-Based Anti-Jamming Techniques in Sensor
  Networks, Nov 2005
• 3 Y.W. Law, P. Hartel, J. den Hartog, P.
  Havinga, Link-layer Jamming Attacks on S-MAC,
  Proc. 2nd European Workshop on WSN, Feb 2005, pp.
  217-225
• 4 Y.W. Law, L. van Hoesel, J. Doumen, P.
  Hartel, P. Havinga, Energy-Efficient Link-Layer
  Jamming Attacks against Wireless Sensor Networks
  MAC Protocols, Proc. 3rd ACM workshop on
  Security of ad hoc and sensor networks, Nov.
  2005, pp. 76-88
• 5 A. D. Wood, J.A. Stankovic, S.H. Son, JAM A
  Jammed-Area Mapping Service for Sensor Networks,
  Proc. 24th IEEE Intl. Real-Time System Symposium,
  2003, pp. 286-297
• 6 W. Xu, T. Wood, W. Trappe, Y. Zhang, Channel
  Surfing and Spatial Retreats Defenses against
  Wireless Denial of Service, ACM WiSe, Oct. 2004,
  pp. 80-89
• 7 W. Xu, W. Trappe, Y. Zhang, T. Wood, The
  feasibility of Launching and Detecting Jamming
  Attacks in Wireless Networks, ACM MobiHoc, May
  2005, pp.46-57