MANET

Security in Manet Networks Challenges and Solutions

MANETS recent popularity

• Self-configuration
• Self-maintenance

Challenges to security

• Open network architecture
• Shared medium
• Resource constraints
• Dynamic topology

Goals of MANET Security

• Protect network connectivity over multi-hop wireless channels
• Link level solutions + network level solutions

Approaches

• Proactive
• Reactive

Attacks (Network Layer)

• Routing attacks
• Attempt to “screw up” the others’ routing tables (remote effect)
• Forwarding attacks
• Leave routing tables alone, but change delivery of packets (local effect)
• Attack dependent on underlying protocol

Attacks (Link Layer)

• Key attacks
• WEP
• DoS attacks - Manipulation of backoff interval

1. Easy corruption of other’s data
2. Effects are compounded at higher layers
3. Solution Outline – A Multi-fence Security Solution
   

Message Authentication Primitives

• Message authentication code

1. One-way hash function based on shared key
2. Send data + MAC
3. Verified only by intended receiver
4. Low computational overhead
5. Storage requirement
6. O(n2) keys

• Digital signature

1. Public key infrastructure w/ certificates
2. Encrypt w/ private and decrypt w/ public
3. Verified by all receivers
4. High computational overhead
5. Storage requirement
6. O(n) keys
7. Certificate revocation lists
8. Less resilient to DoS attacks

Secure Routing

• Usually proactive approach
• Authenticate source and routing information
• Based on routing protocols
• Source-based routing
• Distance vector routing
• Link state routing

Secure Source-based Routing

• Append node ids to dynamically create routing path
• Goal: Prevent intermediate nodes from altering routing list
• End-to-end verification of nodes in paths
• Example protocol (Adriadne) uses hash chaining technique

Secure Distance Vector Routing

• Advertise global shortest paths to neighbor
• Based on a distance metric
• Goal: ensure correct advertisement of distance metric and authentic sender
• Authenticate aggregation of metric
• Unclear example in the paper that used hash chain on hop count

Secure Link State Routing

• Discover neighbors and broadcast that info to everyone
• Links only added if bidirectional
• Nodes can collude
• Goal: authenticate both neighbor discovery and neighbor broadcast
• Example protocol (SLSP) uses digital signatures

Secure Packet Forwarding

• Prevention impossible
• Detection
• Monitor neighbors
• Probe path (for failures)
• Reaction
• Related to prevention mechanism
• Global
• End-host

Open Challenges

• Larger problem space
• Thwart attacks but include failures, misconfigurations, and network overload
• Intrusion toleration
• Make system robust in the presence of attacks
• Larger solution space
• Supplement encryption with other mechanisms (connectivity or route redundancy)
• Use redundancy on system and protocol levels

Conclusions

High level description of security issues in MANETSFocused on network layer. Especially routing
Proposed “resiliency-oriented” multi-layered solution design – increased fault tolerance in security systems and called for better analysis models.