Malware MD5 or file search
File MD5 Hash:
This service allows you to query their database of many unique malware samples for a computed MD5 hash of a file. If it is malware and they know about, they return the last time they have seen it along.
MD5 hash database should not be intended as a substitute for an security/antivirus solution, instead it provides you an additional layer of detection, allowing you to identify known suspicious files.