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Security of wireless ad-hoc networks

Security of wireless ad-hoc networks. Outline. Properties of Ad-Hoc network Security Challenges MANET vs. Traditional Routing Why traditional routing protocols not suitable for MANET networks? Routing protocols for MANET Nodes misbehave Routing Security Schemes.

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Security of wireless ad-hoc networks

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  1. Security of wireless ad-hoc networks

  2. Outline • Properties of Ad-Hoc network • Security Challenges • MANET vs. Traditional Routing • Why traditional routing protocols not suitable for MANET networks? • Routing protocols for MANET • Nodes misbehave • Routing Security Schemes

  3. Properties of Ad-Hoc network (1) • No fixed topology • Each node is a router • Limited energy • Limited CPU and other resources • Transient connectivity and availability • Shared physical medium • Identity different from address • Physical vulnerability • Lack of central administration

  4. Properties of Ad-Hoc network (2) • Where Ad hoc network • Installing an infrastructure is not possible • The network is too transient • The infrastructure was destroyed • Throughput

  5. Security Challenges • Confidentiality • Encryption and access control with authentication • Integrity • Also require cryptographic keys • Availability • Results in two fundamental problem • Trust establishment, key management and membership control • Network availability and routing security

  6. MANET vs. Traditional Routing (1) • Every node is potentially a router in a MANET, while most nodes in traditional wired networks do not route packets • Topologies are dynamic in MANETs due to mobile nodes, but are relatively static in traditional networks • MANET topologies tend to have many more redundant links than traditional networks

  7. MANET vs. Traditional Routing (2) • A MANET router typically has a single interface, while a traditional router has an interface for each network to which it connects • Power efficiency is an issue in MANETs, while it is normally not an issue in traditional networks • Low bandwidth links, high bit error rates, frequent changes in network topology, battery-powered devices with limited transmitter power

  8. Why traditional routing protocols not suitable for MANET networks? • MANETs are usually highly dynamic. • No pre-existing infrastructure. • No centralized administration. • Dynamic topologies. • Energy-constrained nodes. • Limited physical security.

  9. Routing protocols for MANET • IETF MANET working group • Categories • Proactive=Periodic topology updates • Reactive=On-demand driven protocol • Hierarchial • Protocols • DSR (draft), FSR, DSDV, TORA, ZRP, AODV (RFC 3561), OLSR (RFC 3626), TBRPF (RFC 3684)

  10. Nodes misbehave • Overloaded • Selfish • Malicious • broken

  11. Solutions to misbehaving node • A priori trust relationship • Forsake or isolate these nodes form within the actual routing protocol for the network • Install extra facilities in the network to detect and mitigate routing misbehavior

  12. Routing Security Schemes • Watchdog and Pathrater • SEAD • SRP

  13. Watchdog and pathrater • Two extensions to the Dynamic Source Routing (DSR) to help mitigate routing failures and attacks in ad-hoc networks • Watchdog: identifies misbehaving nodes • Pathrater: avoids routing packets through these nodes

  14. DSR • Route discovery Source May receive many ROUTE REPLY

  15. Link break notify DSR (cont.) • Route maintenance • Handles link breaks Link break occurred S A B D • Try another path • Do a route discovery B moves out of transmission range of A

  16. Watchdog

  17. Pathrater • Run be each node in the network • Rating for every other node • Path metric • If multiple paths • Highest metric

  18. Watchdog’s weaknesses • Ambiguous collisions • Receiver collisions • False misbehavior • Partial dropping

  19. Ambiguous/receiver collisions • Ambiguous • Prevents A from overhearing transmissions from B • If repeatedly fails to detect B forwarding on packets, then A assume B misbehaving • Receiver • B could be selfish or malicious (wastes resource)

  20. False misbehavior • Nodes falsely report other nodes as misbehaving 1. S mark B as misbehaving 2. S wonder why received replied P P P S A B D F A A A 1. If A drops Ack Packet 2. B detects this misbehavior and reports it to D

  21. Partial dropping • A node can circumvent the watchdog by dropping packets at a lower rate than the watchdog's configured minimum misbehavior threshold.

  22. NIST BSAR

  23. pros and cons

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