Timing Side Channel Attacks

I had an interesting discussion with Bob McMillian of IDG yesterday about the potential for timing attacks in the cloud. Timing attacks are a kind of side channel attack that is based on observed behavior of a cryptographic system when fed certain inputs. Given enough determinism in the response time of the system, it may be possible to crack the cryptosystem based on a statistical sampling of its response times taken over many transactions.

Bob was interested in my thoughts about the threat this attack vector represents to cloud-resident applications. It’s an interesting question, because I think that the very characteristics of the cloud that people so often criticize when discussing security—that is, multi-tenancy and the obfuscation of actual physical resources by providers—actually work to mitigate this attack because they add so much non-deterministic jitter to the system.

Bob’s excellent article got picked up by a number of sources, including ComputerWorld, LinuxSecurity, InfoWorld. It’s also been picked up by the mainstream media, including both San Francisco Chronicle and the New York Times.