W97M/Mutalisk.A is a MS Word 97 polymorphic macro virus. The polymorphism consist of modifying the commented lines.
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.
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 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.
Every time when infect documents the virus beep and shows its code by running the VBA Editor. At the same time it tries to be stealth by deleting the virus code when the user starts the VB Editor. After that it rebuilds itself. In addition it saves the active document as c:\ReadMe.doc.
One of the virus payload is that every time when an infected file is opened or a new is created it will try to delete Anti-Virus products installed on the users computer.
The other payload of W97M/Mutalisk.A uses mIRC chat application if it is installed. It will try to overwrite the script.ini file with its own. At the same time it saves the active infected document as c:\mirc\backup\Y2K.doc. Next time when mIRC is used it will try to send out this infected document.
Mutalisk.A also hooks Tools/Macro and File/Templates menus.
Variant:Mutalisk.B
This variant is similar to W97M/Mutalisk.A except that it doesn't save the active document as c:\ReadMe.doc when the user open VB Editor.