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

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

Suspect a file is incorrectly detected (a False Positive)?

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest detection database updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    NOTE If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note You need administrative rights to change the settings.

For more Support


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User Guide

See the user guide for your product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

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.