Jam me if you can: Mitigating the Impact of Inside Jammers

Nov 16, 2011

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Abstract

The open nature of the wireless medium leaves wireless communications exposed to interference caused by the concurrent operation of co-located wireless devices over the same frequency bands. While unintentional signal interference is managed at the physical and mac layers using an array of techniques (advanced signal processing, channel coding and error correction, spread spectrum communications, multiple access protocols, etc.), in a hostile environment, wireless communications remain vulnerable to intentional interference attacks typically referred to as jamming. Jamming can take the form of an external attack launched by "foreign" devices that are unaware of the network secrets (e.g., cryptographic credentials) or its protocols. Such external attacks are relatively easy to neutralize through a combination of cryptography-based measures and
spreading techniques. In contrast, when jamming attacks are launched from compromised nodes, they are much more sophisticated in nature.

These attacks exploit knowledge of network secrets (e.g., cryptographic keys and pseudo-random spreading codes) and its protocol semantics to maximize their detrimental impact by selectively and adaptively targeting critical data transmissions. In this talk, we
discuss the feasibility and impact of selective jamming attacks in the presence of inside adversaries. The attacker's selectivity is considered at different granularities, namely on a per-channel basis and on a per-packet basis. We describe several mitigation methods that
do not rely on the existence of shared secrets, but defeat selectivity via a combination of temporary packet hiding and uncoordinated frequency hopping.