Natas is a highly polymorphic virus that has been reported to be in the wild in USA and in several other locations - it is especially common in Mexico.
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.
Natas infects COM, EXE and overlay files and both MBR's on hard disks and DOS boot records on floppies.
Natas is also a stealth virus, hiding its presence when it is resident in memory. This makes Natas one of the few known polymorphic stealth viruses; only Tremor, Uruguay, and Neuroquila have implemented similar functionality. The stealth mechanisms in Natas are quite tricky; whenever a known archiver is executed, the stealth routines are disabled. The virus does this in order to make sure it gets a chance to spread from a machine to another.
Natas is a destructive virus. It activates in 1/512 probablity when an infected file is executed. The desctruction routine is also executed if the virus detects a debugger. When activating, the virus overwrites most of the first hard drive in the system.
There are four known variants, 4744, 4746, 4774 and 4988 bytes in length. They contain several different internal texts, like:
Natas BACK MODEM Time has come to pay (c)1994 NEVER-1 Yes I know my enemies. They're the teachers who taught me to fight me Compromise, conformity, assimilation, submission Ignorance, hypocrisy, brutality, the elite All of whitch are American dreams (c) 1994 by Never-1(Belgiëum Most Hated) Sandrine B.
The author of this virus, James G alias Priest alias Little Loc has also written several other viruses, including Predator, Jackal and Sat_Bug.