F-Secure Virus Descriptions : Natas

NAME:	Natas
TYPE:	Resident MBR Boot sectors COM/EXE-files
ORIGIN:	USA

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.

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(Belgium 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.