Cmpe 259
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CMPE 259. Sensor Networks Katia Obraczka Winter 2005 Security. Announcements. Hw3 due today. Project presentations tomorrow from 4-7pm. Project reports due tomorrow by midnight. Security in sensor networks. Security in sensor networks.

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CMPE 259

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Cmpe 259

CMPE 259

Sensor Networks

Katia Obraczka

Winter 2005

Security


Announcements

Announcements

  • Hw3 due today.

  • Project presentations tomorrow from 4-7pm.

  • Project reports due tomorrow by midnight.


Security in sensor networks

Security in sensor networks


Security in sensor networks1

Security in sensor networks

  • For many sensor network applications, security is critical.

    • Public safety, special operations, healthcare, etc.

  • Sensor network protocols should incorporate security mechanisms in the original design.


Dos in sensor networks wood et al

DoS in Sensor Networks [Wood et al.]

  • What is DoS?

    • Attack that reduces or eliminates the network’s ability to perform its function.

    • E.g., hardware failures, software bugs, resource exhaustion, etc.

  • Paper looks at protocol layers and possible DoS attacks.


Physical layer

Physical layer

  • Attacks:

    • Jamming.

    • Tampering.

  • Defenses:

    • Jamming:

      • Spread-spectrum techniques.

      • Lower duty cycle with priority messages.

      • Alternate modes of communication.

    • Tampering:

      • “Self-destruction”

      • Hiding nodes.


Link layer

Link layer

  • Attacks:

    • Collision induction.

    • Battery exhaustion.

    • Unfairness.

  • Defenses:

    • Collision induction.. Fairness.

      • Error correcting codes (?) .Small frames.

      • Collision detection.

      • Collision-free MAC.

    • Battery exhaustion.

      • Rate limitation.

      • Streamlined protocols.


Network layer attacks

Network layer: attacks

  • “Neglect and greed”.

  • “Homing”.

  • Misdirection.

  • Gray/black holes.


Network layer defenses

Network layer: defenses

  • Authorization.

    • Only authorized nodes participate in routing.

      • Need authentication mechanisms.

    • Monitoring.

      • Monitor node behavior.

    • Probing.

    • Redundancy.


Transport layer

Transport layer

  • Attacks:

    • Flooding.

    • Desynchronization.

      • Message fabrication to get end points out of sync.

  • Defenses:

    • Flooding:

      • Limit number of connections.

      • Challenges/puzzles to clients.

    • Desynchronization:

      • Authenticate all messages (including header fields)


Sample protocol vulnerabilities

Sample protocol vulnerabilities

  • Adaptive rate control [Woo et al.]

    • MAC layer modifications to 802.11.

    • Preference to route-through traffic.

    • Vulnerabilities?

  • RAP [Lu et al.]

    • Similar vulnerability.

    • Differentiated services can be exploited by attacker.


On communication security slijepcevic et al

“On Communication Security…” [Slijepcevic et al.]


Focus

Focus

  • Communication security in sensor networks.

  • Data classification and related security threats.

  • Location-based security mechanism.


Types of data

Types of data

  • Mobile code.

  • Sensor node location.

  • Application data.

  • Goals:

    • Minimize security-related energy consumption.

    • Different protection levels.


Target sensor net architecture

Target sensor net architecture

  • Localized algorithms.

  • Local broadcast.

  • Mobile code.


Security threats

Security threats

  • Insertion of malicious code.

  • Interception of messages with node location information.

  • Interception of application data.

  • Injection of false data.

Lower risk.


Security architecture

Security architecture

  • Symmetric key encryption.

    • All messages encrypted.

  • Three security levels:

    • Level I: mobile code.

    • Level II: node location information.

    • Level III: application data.

  • Encryption strength:

    • Level I > level II > level III.

  • Encryption algorithm with adjustable strength (number of rounds).


Security architecture cont d

Security architecture (cont’d)

  • Group keys.

  • Every user: set of keys, pseudorandom generator, and seed.

  • Periodically and synchronously, nodes change keys.


Security levels

Security levels

  • Level I uses strongest encryption for mobile code injection.

    • 32 rounds.

  • Level II:

    • Location-based keys.

      • Different for different “cells”.

      • Protect network from compromised keys.

  • Level I:

    • Weakest security.

    • 22 rounds.


Performance

Performance

  • Cost of encryption/decryption.

  • Energy considerations.

    • Rockwell WINS node.


Secure routing karlof et al

“Secure Routing…” [Karlof et al.]


Focus1

Focus

  • Routing security in sensor networks.

  • Problem:

    • Current routing protocols for sensor networks do not consider security.

    • Vulnerable to attacks.

    • Not easy to make these protocols secure.


Contributions

Contributions

  • Threat models and security goals for sensor network routing.

  • Two new attacks: sinkhole and HELLO floods.

  • Security analysis of routing and topology control algorithms.

  • Attacks against these protocols.

  • Countermeasures and design issues for secure routing in sensor networks.


Deployment and platform

Deployment and platform

  • Heterogeneous deployment.

  • Mica motes with TinyOS.

  • Base stations.

  • Aggregation points.


Sensor and ad hoc networks

Sensor- and ad-hoc networks

  • Traffic considerations:

    • Ad hoc networks exhibit more general patterns.

    • Sensor networks:

      • Many-to-one.

      • One-to-many.

      • Local.

  • Capabilities.

    • Sensor nodes are typically more limited.

  • Trust relationships.

    • E.g., to perform aggregation, duplicate pruning, etc.


Attacks

Attacks

  • Spoofed, altered, replayed routing information.

  • Selective forwarding.

    • Black/gray hole.

  • Sinkhole.

  • Sybil.

    • Single nodes presents multiple id’s to others.

  • Wormhole.

  • HELLO flood.

  • (Link-layer) ACK spoofing.


Countermeasures

Countermeasures

  • Outsider attacks:

    • Link layer encryption and authentication.

    • Shared keys.

  • Insider attacks:

    • Identity verification.

    • Multipath routing.

    • Bi-directional link verification.

    • Limiting number of neighbors.

  • Sinkhole and wormhole attacks are harder to circumvent.

    • Design routing protocols where these attacks are ineffective.

    • E.g., geographic routing. ???


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