"Fine grain Cross-VM Attacks on Xen and VMware are possible" and OpenSSL 0.9.7
Actually the authors used both OpenSSL 0.9.7 and 1.0.1; they detail the differences between the versions, what changed in the implementations, and what they can do from other VM.

They refer to 0.9.7 because that was the version used by Bernstein in 2003 when he worked on cache-timing attacks on AES. This allows to highlight how much (or how little) the cross-VM boundary complicates things for the attacker. They also did tests on 1.0.1, since that's the current, modern version.