[PPT] - A Test-Bed for Mobile Ad-hoc Networks How Much Can Watchdogs Really PowerPoint Presentation

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 1

A Test-Bed for Mobile Ad-hoc Networks

How Much Can Watchdogs Really Do?

Sonja Buchegger, Cedric Tissieres, Jean-Yves Le Boudec EPFL (Swiss Federal Institute of Technology Lausanne) WMCSA, December 3, 2004

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 2

Presentation Outline

Problem: Detecting Misbehavior in Mobile Ad-hoc

Networks

Attacks on Dynamic Source Routing (DSR)
Detectability of Attacks
Proposed Solution:
Enhanced Passive Acknowledgment
Test-Bed
Performance Evaluation: Some Experimental Results
Related Work
Conclusions

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 3

Mobile Ad-hoc Networks

Network of devices, no infrastructure, nodes forward packets for others. Nodes cooperate to communicate.

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 4

But Why Cooperate? Misbehavior Pays Off

Selfish: to save power

Example: No or incorrect forwarding

Malicious: to attack the net

Example: Route deviation

Faulty: (no reason)

Example: Repeating packets

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 5

Here’s the Dilemma!

Tragedy of the Commons: Free ground for everyone to let sheep graze Individually: good to put many sheep Overall: too many sheep!

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 6

Problem Statement

How can we make a system work despite misbehavior?
Which types of misbehavior are actually detectable and

how?

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 7

Background: Dynamic Source Routing (DSR)

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 8

DSR - Route Request

R

u

t e R e q u e s t ( D [ A , B ] )

A B C D E

Route Request(E[A]) Route Request(E[A]) R

u

t e R e q u e s t ( E [ A , B ] ) Cache: E Route Request (E[A,B]) Route Request(E[A,C])

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 9

DSR - Route Reply

A B C D E

Route Reply(A, [E,B,A]) Route Reply(A, [E,D,C,A]) Route Reply(A, [E,D,C,A]) Route Reply(A, [E,B,A]) Cache: E

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 10

DSR – Data

A B C D E

Data(E, [A,C,D]) Cache: E Data(E, [A,C,D]) D a t a ( E , [ A , C , D ] )

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 11

Acknowledgments in DSR

Explicit ACK
Passive ACK
Link-layer notification

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 12

Enhanced Passive Acknowledgment

PACK: Overhearing of
Forwarding
Tampering
Fabrication
In addition: Packet

Reception

A B C

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 13

Attacks on DSR

Dropping Attacks
All or partial
Omit Route Error
Modification Attacks
Forged routing packets
Added nodes
Last Hop External
Salvage intact routes
Loops
Tamper with RREQ, RREP
Decrease TTL
Fabrication Attacks
Forged RERR
Spoofed RREQ
Forged RREP
Frequent RREQ
Timing Attacks
RREP

disproportionally fast

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 14

Test-Bed Components

Piconet with PACK, enhanced PACK, and

attacks

APE
Netfilter with promiscuous mode
Pcmcia-cs with promiscuous mode
Setup: Laptops with Linux kernels 2.4.19 and

2.4.20, Orinoco Classic Gold 802.11b cards

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 15

Test-Bed Architecture

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 16

Implemented Example Attacks

Header Modification
Selfish Attacks
Remove from RREP
RERR modification
Attacks work!
Malicious Attacks
Change Source Route
RERR destination
Attacks work!
Partial Dropping
Attack works!
RERR Fabrication
Attack works!

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 17

Experimental Results

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 18

Experimental Results II

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 19

Related Work: Economic Incentives

Forwarding is

rewarded.

Target: selfish/rational

nodes

Examples:

nuglets/counters, Crowcroft, Sprite

Solution only for the

non-forwarding type of misbehavior.

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 20

Related Work: Secure Routing

Solution only for route
discovery. Nodes can

still deviate traffic or drop packets.

Using Cryptography to

secure route discovery

Target: malicious

nodes

Examples: Ariadne,

SRP, S-AODV, BISS

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 21

Related Work: Reputation Systems 1

In MANET or P2P:
Keep track of

misbehaving nodes, exclude them

Target: misbehaving

nodes regardless of reason

Examples: Watchdog,

CORE, Context, OCEAN, ID, Aberer, SECURE

Either
Use only first-hand

information, so only detect neighbors, or

are vulnerable to

spurious ratings, or

assume trust

transitivity, or

nly consider

negative (positive) information

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 22

Related Work: Reputation Systems 2

Centralized
E-Commerce
History of

transactions for future choice of partners

Target: human

decision makers, agents

Examples: E-Bay

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 23

Solution Proposal: CONFIDANT

Target both routing and forwarding misbehavior
Regardless whether selfish, faulty, or malicious
Be able to detect misbehavior before meeting (use

second-hand information)

Cope with spurious ratings
Fully distributed

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 24

Purpose of CONFIDANT

CONFIDANT detects misbehaving nodes

✁

by means of observation or reports about several types of attacks

and thus allows nodes

✁

to route around misbehaved nodes and

✁

to isolate misbehaved nodes from the network, so that misbehavior

✂

does not pay off,

✂

cannot continue, and

✂

routes are functional.

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 25

F A B E C D G

Misbehavior

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F A B E C D G

Publication

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 27

F A B E C D G

Isolation and Rerouting

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 28

Conclusions

Watchdogs can work well
Enhanced Passive ACK can detect quite a lot
Watchdogs with enhanced PACK can give useful

input to misbehavior detection and reputation systems

Need to do larger test-bed experiments to find

limitations, false positives

Make code and documentation freely available

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12/3/04 A Test-Bed for Mobile Ad-hoc Networks S. Buchegger, C. Tissieres, JY. Le Boudec 29

Watch This Space!

Code and Documentation will be available from
http://icapeople.epfl.ch/sbuchegg
Soon.