Backhand

Summary

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

Removal

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Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More

Detailed instructions for F-Secure security products are available in the documentation found in the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for further assistance.

Technical Details

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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