Skulls.F is an edited version of Skulls.D SIS file trojan, it contains several variants of Cabir worm, and several copies of Locknut.B trojan.
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 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.
Skulls.F is still under analysis, detailed information will be provided in near future.
Spreading in: Simworks.SIS and WMAcodec.sis
Replaces built in and third party applications with non-functional ones, installs Cabir worm variants, Locknut.B trojan and starts animation that shows flashing skull picture.