Blakday trojan/ worm( W32.Whacker.A by Symantec) is a very very nasty malware. It overwrites a lot of data file types and executables with a copy of its own and makes a total mess of your system. Moreover it puts its copies with autorun.inf files on all partitions, drives and USB sticks etc. Very scary malware indeed. Let,s see how some of the HIPS fare against this malware.