New Branch Prediction Vulnerabilities in OpenSSL and Necessary Software Countermeasures

Abstract. Software based side-channel attacks allow an unprivileged spy process to extract secret information from a victim (cryptosystem) process by exploiting some indirect leakage of “side-channel” information. It has been realized that some components of modern computer microarchitectures leak certain side-channel information and can create unforeseen security risks. An example of such MicroArchitectural Side-Channel Analysis is the Cache Attack — a group of attacks that exploit information leaks from cache latencies [4, 7, 13, 15, 17]. Public awareness of Cache Attack vulnerabilities lead software writers of OpenSSL (version 0.9.8a and subsequent versions) to incorporate countermeasures for preventing these attacks. In this paper, we present a new and yet unforeseen side channel attack that is enabled by the recently published Simple Branch Prediction Analysis (SBPA) which is another type of MicroArchitectural Analysis, cf. [2, 3]. We show that modular inversion — a critic...

• Type: Conference
• Year: 2007
• Where: IMA
• Authors: Onur Aciiçmez, Shay Gueron, Jean-Pierre Seifert
• Keywords: Cache Attack, Extended Euclidean Algorithm, IMA 2007, Side-channel Attacks