Enhanced TKIP Michael Attacks

Abstract

This paper presents new attacks against TKIP within IEEE 802.11 based networks. Using the known Beck-Tews attack, we define schemas to con- tinuously generate new keystreams, which allow more and longer arbitrary packets to be injected into the network. We further describe an attack against the Michael message integrity code, that allows an attacker to concatenate a known with an unknown valid TKIP packet such that the unknown MIC at the end is still valid for the new entire packet. Based on this, a schema to decrypt all traffic that flows towards the client is described.