Threat Description



Category: Malware
Platform: W32
Aliases: MtE, Mutation Engine


This is not really a virus, but a "add-on" product supplied by the person who calls himself Dark Avenger. It can be used to give any virus a "polymorphic" ability, making it undetectable with a signature-based scanner.


Automatic action

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

More scanning & removal options

More information on scanning or removal options is available in the documentation for your F-Secure security product on the Downloads section of our Home - Global site.

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

Contact Support

For further assistance, F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

Technical Details

Instead an algorithmic approach is used, which may (theoretically) produce false alarms. So, if F-Secure anti-virus products ever report a single file as containing MtE, don't be too alarmed - it might just be a false positive. If you get an alarm from a data file (non-executable), it's a certain false positive. Send a sample and we'll fix it.

One known false alarm is a file called 120492_v.dxf. If you find MtE from this file, simply ignore it.

Another known false alarms is from a data file called bf1g2.acm. This file is from a game called Baldur's Gate. If you find MtE from this file, simply ignore the false alarm. We are working to fix this.

Several viruses are known to make use of this Mutation Engine:


Other: Resident, COM-files

A variant of the Gotcha virus.

Variant:Dedicated, Fear

Other:Non-Resident, COM-files

Those two viruses are almost identical - but with different text messages. They would be considered totally unremarkable, if not for the inclusion of the engine.


Other: Resident, COM/EXE-files

This virus is targeted against several anti-virus product, attacking their data files.


Other: Non-Resident, COM-files

Unknown effects.


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