There is a new piece of malware doing the rounds against which the security authors have as yet not managed to write a defense......nor are they sure exactly what is the purpose or threat posed by this file.
This thing styles itself AvastAntivirus or Avast!Antivirus and is found in C:\Windows\system32
For those with genuine Avast installed......this is not a genuine file.
The only defense against it at the moment appears to be Malwarebites which can quarantine but not clean this thing.
Will update if any more info. becomes available.