Nodes Bearing Grudges: Towards Routing Security, Fairness, and Robustness in Mobile Ad Hoc Networks

1
Nodes Bearing Grudges Towards Routing Security,
Fairness, and Robustness in Mobile Ad Hoc Networks

• Sonja Buchegger
• Jean-Yves Le Boudec

2
Security Issues

• Cooperation and fairness
• Traffic forwarding
• Resource saving
• Confidentiality of location
• Military
• Privacy
• No traffic diversion
• Routing
• Forwarding

3
Motivation

• Resource conservation (selfish)
• Better service
• Monetary gains
• Competition
• Stealing

4
Detection and Reaction

• Want to punish malicious and non-cooperative
  behavior
• Isolate the problem node
• Implement re-integration into network if possible

5
Secrets and Lies. Digital Security in a
Networked Worldby Bruce Schneier

• a prevention-only strategy only works if the
  prevention mechanisms are perfect otherwise,
  someone will find out how to get around them.
• In theory there is no difference between theory
  and practice. In practice there is

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The Selfish Gene

• Suckers
• Cheats
• Grudgers

7
The Grudger Protocol

• Observe node behavior
• Share information
• Components
• Monitor (Neighborhood Watch)
• Trust Manager
• Reputation System (Node Rating)
• Path Manager

8
Observation

• Ad hoc network
• Node A sends packet destined for E, through B.
• B keeps packet copy.
• B snoops D.

A
E
B
D
C
9
The Monitor

• No forwarding
• Unusual traffic attraction
• Route salvaging
• No error messages during errors
• Unusually frequent route updates
• Silent route changes

10
The Trust Manager

• Trust function
• Trust level administration
• Forwarding of ALARM messages
• Filtering of incoming ALARM messages

11
The Reputation System

• Own experience greatest weight
• Observations lesser weight
• Reported experience PGP trust weight

12
The Path Manager

• Path re-ranking based on security metric
• Deletion of paths containing malicious nodes
• Route request from malicious node
• Request for route containing malicious node

13
Within the Node

• Monitor checks behavior of neighbors
• Events are forwarded to Reputation system
• If an event threshold is broken, rating for
  offending node is updated
• If rating of offending node drops below
  acceptable threshold, the Path Manager removes
  routes containing offending node
• ALARM message is sent by the Trust Manager

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ALARM

• Sent by the Trust Manager
• Type of protocol violation
• Number of occurrences observed
• Whether the message was self-originated by the
  sender
• Address of the reporting node
• Address of the observed node
• Destination address

15
Between nodes

• Monitor receives ALARM
• Trust Manager checks rating of source
• Reputation System updates number of occurrences
  and accumulated rating
• Note
• Either the source is fully trusted, or several
  partially trusted nodes have added to one
  completely trusted note
• Authentication is a prerequisite

16
Dynamic Source Routing (DSR)
17
Dynamic Source Routing (DSR)
18
Attacking DSR

• Incorrect forwarding
• Traffic attraction
• Route salvage for unbroken link
• Short reply time
• Set good metrics for bogus routes
• Manipulate flow metrics
• No Route Errors sent
• Use bogus routes
• Promiscuous mode to spy on traffic
• DoS route updates at short intervals

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Grudging Nodes
X
Data (A,C,D,E)
20
Grudging Nodes
21
Testing

• Performance Analysis of the CONFIDANT Protocol
  (Cooperation Of Nodes Fairness In Dynamic Ad-hoc
  NeTworks)
• GLOMOSIM
• Malicious nodes (Incorrect forwarding)
• DSR modifications
• Fortified vs. Defenseless networks

22
Fixed Parameters

• Area 1000m x 1000m
• Speed uniformly distributed between 0 and 20 m/s
• Radio Range 250m
• Placement uniform
• Movement Random Waypoint
• MAC 802.11
• Sending Capacity 2 Mbps
• Application CBR
• Packet Size 64 B
• Simulation Time 900s

23
Varied Parameters

• Percent of malicious nodes 0 100
• Pause time 0 900s
• Number of nodes 10 50

Metrics

• Dropped packets (mean, )
• Goodput
• Packets Received / Packets Originated

24
Results

• Every non malicious node was a friend
• Defenseless network 70 packet loss
• Fortified network gt3 packet loss
• Overhead is small (ALARM messages)
• Performance is good even with up to 60 malicious
  nodes
• Pause time had the least performance influence

25
Research Pieces

• Event detection
• Dropped packets
• Mis-routed packets
• TCP Syn flood
• Distributed Trust
• Friends
• No guarantee of connection to authority
• Transitive relations

26
Follow-on

• Distributing reputations
• Authentication
• Immune Networking
• Based on the bodys immune system
• Goals
• Learns through observations
• Adapts to environment

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Algorithm

• Ad hoc network
• Node A sends packet destined for E, through B.
• B and C make snoop entry (A,E,Ck,B,D,E).
• B and C check for snoop entry.
• Perform Misroute

A
E
B
D
C