Threat Description

Backhand

Details

Aliases: Backhand, Backhand.A
Category: Malware
Type:
Platform: W32

Summary



Backhand is a polymorphic Word 97 macro virus which payload simulates the Y2K-problem.



Removal



Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.



Technical Details



The virus replicates when an infected document is opened, closed or a new one is created.

Backhand.A first disables the build-in macro virus protection. After that it drops its code in a file "sysboot.bin" to the root of "C:" drive and uses it to infect global template and documents.

When infects documents the virus change some of its subroutine names with random ones.

The virus contains a few payloads. First of them activates when the day of the month is 13. Than it saves the active document with a random password and shows a message:

        Your document has been corrupted because of a bug in Word!
        Call Microsoft Customer Support, they can help you. When you
        call, tell them this Bug-ID Code (don't forget it!)

If the day is also Friday then Backhand.A shows another message:

         Have A Nice Day!
         It's Friday 13th! This is my lucky day, I hope it's
         yours too!

The last payload activates in year 2000 or later when Backhand.A change the system date to January 1st 1980.





Technical Details: Katrin Tocheva, F-SECURE


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