US Patent 7908657 Detecting variants of known threats

Detecting a variant of a known threat is disclosed. A portion of network traffic is matched with at least a portion of a signature associated with the known threat. If the portion of network traffic being matched with the signature does not exactly match the signature, the extent of match between the portion of network traffic and the signature is determined. If the extent of match satisfies a threshold, a security response is triggered based upon the extent of match.