Today we have spotted a batch of messages arriving in our spam systems titled "Conflicker.B Infection Alert". The message goes like this:
Dear Microsoft Customer,
Starting 12/11/2009 the "˜Conficker' worm began infecting Microsoft customers unusually rapidly. Microsoft has been advised by your Internet provider that your network is infected.
To counteract further spread we advise removing the infection using an antispyware program. We are supplying all effected Windows Users with a free system scan in order to clean any files infected by the virus.
Please install attached file to start the scan. The process takes under a minute and will prevent your files from being compromised. We appreciate your prompt cooperation.
Microsoft Windows Agent #2 (Hollis)
Microsoft Windows Computer Safety Division
The fact that the so-called antispyware program comes attached with the email is a good indication that something is not looking right.
When the attached program was executed, it did not start a "free system scan" as claimed, but instead it simply moved itself into other folders in the system and have set up itself to be automatically started on windows startup.
Not surprisingly, the attached file is detected by Sophos as Mal/FakeAV-AX and the email message has also been blocked.
This is another example of social engineering tricks employed by malware authors to capitalize on fears of the user to entice them into running malicious software.
As always with dealing with emails, think twice before running what came with the attachment.