Cache Side Channel Research Articles

CacheAudit

We present CacheAudit, a versatile framework for the automatic, static analysis of cache side channels. CacheAudit takes as input a program binary and a cache configuration and derives formal, quantitative security guarantees for a comprehensive set of side-channel adversaries, namely, those based on observing cache states, traces of hits and misses, and execution times. Our technical contributions include novel abstractions to efficiently compute precise overapproximations of the possible side-channel observations for each of these adversaries. These approximations then yield upper bounds on the amount of information that is revealed. In case studies, we apply CacheAudit to binary executables of algorithms for sorting and encryption, including the AES implementation from the PolarSSL library, and the reference implementations of the finalists of the eSTREAM stream cipher competition. The results we obtain exhibit the influence of cache size, line size, associativity, replacement policy, and coding style on the security of the executables and include the first formal proofs of security for implementations with countermeasures such as preloading and data-independent memory access patterns.

Know Thy Neighbor: Crypto Library Detection in Cloud

Abstract Software updates and security patches have become a standard method to fix known and recently discovered security vulnerabilities in deployed software. In server applications, outdated cryptographic libraries allow adversaries to exploit weaknesses and launch attacks with significant security results. The proposed technique exploits leakages at the hardware level to first, determine if a specific cryptographic library is running inside (or not) a co-located virtual machine (VM) and second to discover the IP of the co-located target. To this end, we use a Flush+Reload cache side-channel technique to measure the time it takes to call (load) a cryptographic library function. Shorter loading times are indicative of the library already residing in memory and shared by the VM manager through deduplication. We demonstrate the viability of the proposed technique by detecting and distinguishing various cryptographic libraries, including MatrixSSL, PolarSSL, GnuTLS, OpenSSL and CyaSSL along with the IP of the VM running these libraries. In addition, we show how to differentiate between various versions of libraries to better select an attack target as well as the applicable exploit. Our experiments show a complete attack setup scenario with single-trial success rates of up to 90% under light load and up to 50% under heavy load for libraries running in KVM.