New attacks on ISO key establishment protocols

Cheng and Comley demonstrated type flaw attacks against the key establishment mechanism 12 standardized in ISO/IEC 11770-2:1996. They also proposed enhancements to fix the security flaws in the mechanism. We show that the enhanced version proposed by Cheng and Comley is still vulnerable to type flaw attacks. As well we show that the key establishment mechanism 13 in the above standard is vulnerable to a type flaw attack

Non-collaborative Attackers and How and Where to Defend Flawed Security Protocols (Extended Version)

Security protocols are often found to be flawed after their deployment. We present an approach that aims at the neutralization or mitigation of the attacks to flawed protocols: it avoids the complete dismissal of the interested protocol and allows honest agents to continue to use it until a corrected version is released. Our approach is based on the knowledge of the network topology, which we model as a graph, and on the consequent possibility of creating an interference to an ongoing attack of a Dolev-Yao attacker, by means of non-collaboration actuated by ad-hoc benign attackers that play the role of network guardians. Such guardians, positioned in strategical points of the network, have the task of monitoring the messages in transit and discovering at runtime, through particular types of inference, whether an attack is ongoing, interrupting the run of the protocol in the positive case. We study not only how but also where we can attempt to defend flawed security protocols: we investigate the different network topologies that make security protocol defense feasible and illustrate our approach by means of concrete examples.Comment: 29 page