In order for the worm to be effective, the administrative password for a machine under attack has to be one of 37 of the worst passwords ever (see below) that it carries in a weak brute-force library.

Yet the worm, which takes over control of remote computers by guessing the password for Remote Desktop, continues to spread, according to watchdogs.

THREAT:

Once attackers gain control of machines they can be used for denial of service attacks, according to a about the worm.

In addition targeting only the lowest hanging fruit, Morto A is notable for being a rare Internet worm, says Mikko Hypponen, chief research officer for F-Secure, in a .