The Inherent Security of Routing Protocols in Ad Hoc and Sensor Networks

Tanya Roosta (EECS, Berkeley)In Collaboration With:

Sameer Pai (ECE, Cornell)Phoebus Chen (EECS, Berkeley)

Prof. Shankar Sastry (EECS, Berkeley)Prof. Stephen Wicker (ECE, Cornell)

April 2, 2008

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Outline

Introduction Problem Setup Attack Scenarios Simulation Setup and Parameters Results Current/Future Work

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Introduction

Generally the focus of routing protocols for sensor networks:

– Energy-efficiency– Guaranteed throughput– Usually involves a non-adversarial setting

Sensor networks are deployed and left unattended– Susceptible to attacks – Must design networks with security in mind

Our work– Determine the statistical impact of different attacks on sensor

network routing– Determine performance of different families of routing protocols

under particular attack scenarios

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Problem Setup

We abstract away the details of specific attacks and specific routing protocols

Instead we focus on characterizing the statistics of attacks on different classes of routing algorithms

Routing Protocols:– Single-path & Multi-path routing protocols– Deterministic and Probabilistic routing protocols

Attack Scenarios– Adversary has compromised some number of nodes within the

sensor network and has subverted their normal operations– Mote-class, insider attackers alter the data and forward it as

normal– Attacks differ by the locations of the attackers within the

network topology

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Single-Path Routing

Deterministic Single-path Routing– Minimum-weight path routing– Edges are assigned weights– Packets sent on path minimizing sum of weights on edges

contained in the path

Probabilistic Single-path Routing– Like a directed random walk on a graph– Each node assigns a probability to each neighbor node (e.g.

uniform assignment)– Packet sent to next-hop neighbor chosen based on the

assigned probability– Achieves load-balancing in a statistical sense

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Multi-path Routing Protocols

Deterministic Multi-path Routing– k-shortest node-disjoint paths– k-shortest edge-disjoint paths

Probabilistic Multi-path Routing– Each node in the network broadcasts packets to all

neighbors with some probability– Extreme case is probabilistic flooding

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Attack Scenarios

Uniformly distributed attack:– The attacker compromises a number of k nodes

uniformly at random.

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Attack Scenarios

Random walk attack:– The attacker chooses a node to compromise

uniformly at random and then performs a directed random walk towards the periphery of the network.

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Attack Scenarios

Spatial attack:– The attacker chooses a node to compromise

uniformly at random and also compromises all nodes within a set preset radius.

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Simulator

Secure Sensor Network Routing Simulator SSNRS – Built in MATLAB to evaluate routing protocols in

the attack scenarios– Discrete packet-time marching simulator– Allows for use of:

Different channel models Routing topologies Routing protocols Attack scenarios

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Parameters Used in Simulations

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Baseline Average Energy Expenditure

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Results: Uniform Attack

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Results: Directed Random Walk

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Results: Spatial Attack

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Results

Routing performance falls sharply with increasing number of uncooperative nodes (insider attackers)

The performance degrades for most families of routing protocols

Single-path routing performs worst with increasing number of uncooperative nodes

Multi-path routing performs best, but comes at an increased energy cost

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Results (cont.)

The uniformly distributed attackers scenario is most detrimental to successful end-to-end packet delivery

Spatial attacks are highly clustered, attacking nodes have a lower probability of being on a path from the source to the destination

Random walk attacks have performance degradation results between the other two attack scenarios

Probabilistic routing protocols are best to preserve confidentiality.

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Current and Future Work

Problem: We need a way to mitigate misbehavior in ad hoc and sensor networks

– Nodes not forwarding data correctly (uncooperative nodes) during routing can cause major problems

– Only those nodes that are behaving correctly (cooperating) should be authorized to have access to the data

Solution: A trust system for wireless ad hoc and sensor networks

– A trust value is a networked node’s belief (probability) in the ability of other nodes in the network to pass necessary data from this node while preserving data integrity and confidentiality

A local metric for predicting the future behavior of other networked nodes

Assists any node in distinguishing reliable forwarding nodes (cooperative nodes) from unreliable forwarding ones (uncooperative nodes)

Goal: To develop robust trust systems for wireless ad hoc and sensor networks

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References

1. “The Inherent Security of Routing Schemes in Ad Hoc and Sensor Networks”. Tanya Roosta, Sameer Pai, Phoebus Chen, Shankar Sastry, Stephen Wicker. In proceedings of the IEEE Globecom 2007, Washington D.C USA.