Wait a Minute! A fast, Cross-VM Attack on AES

In cloud computing, efficiencies are reaped by resource sharing such as co-location of computation and deduplication of data. This work exploits resource sharing in virtualization software to build a powerful cache-based attack on AES. We demonstrate the vulnerability by mounting Cross-VM Flush+Reload cache attacks in VMware VMs to recover the keys of an AES implementation of OpenSSL 1.0.1 running inside the victim VM. Furthermore, the attack works in a realistic setting where different VMs are located on separate cores. The modified flush+reload attack we present, takes only in the order of seconds to minutes to succeed in a cross-VM setting. Therefore long term co-location, as required by other fine grain attacks in the literature, are not needed. The results of this study show that there is a great security risk to OpenSSL AES implementation running on VMware cloud services when the deduplication is not disabled.