L’Hospital: Self-healing Secure Routing for Mobile Ad-hoc Networks

Mobile ad hoc networks (MANETs) are vulnerable to a myriad of attacks. Purely cryptographic countermeasures are effective against outsiders, but not non-cooperative members including selfish and compromised members. Noncryptographic means like intrusion detection must be devised to answer the challenge. However, as recently studied in “jellyfish attack” [1], the effectiveness of wireless intrusion detection systems (IDS) are limited when security attacks can be “cloaked” under protocol-compliant actions. For instance, since packet loss is common in mobile wireless networks, the adversary can exploit this fact by hiding its malicious intents using compliant packet losses that appear to be caused by environmental reasons. In this paper we study two routing disruption attacks that use non-cooperative network members and disguised packet losses to deplete ad hoc network resources and to reduce ad hoc routing performance. These two routing attacks have not been fully studied in previous research. We propose the design of “self-healing community” to counter these two attacks. Our design exploits the redundancy in deployment which is typical of most ad hoc networks; namely, it counters non-cooperative attacks using the probabilistic presence of nearby “good” cooperative network members. To realize the new paradigm, we devise localized simple schemes to maintain self-healing communities. The localized design virtually constructs a “localized hospital” (L’Hospital) to save the (optimal) route discovered by the underlying routing protocol. We develop an analytic model to prove the effectiveness of our design. Then we design and implement our secure ad hoc routing protocols in simulation to verify the cost and overhead incurred by maintaining the communities. Our study confirms that the community-based security is a cost-effective strategy to make off-the-shelf ad hoc routing protocols secure.