The Confiker Mystery

Network worms were supposed to be dead. Turns out they aren't.

In 2009 we saw the largest outbreak in years: The Conficker aka Downadup worm, infecting Windows workstations and servers around the world.

This worm infected several million computers worldwide - most of them in corporate networks. Overnight, it became as large an infection as the historical outbreaks of worms such as the Loveletter, Melissa, Blaster or Sasser.

Conficker is clever. In fact, it uses several new techniques that have never been seen before. One of these techniques is using Windows ACLs to make disinfection hard or impossible. Another is infecting USB drives with a technique that works *even* if you have USB Autorun disabled. Yet another is using Windows domain rights to create a remote jobs to infect machines over corporate networks.

Possibly to most clever part is the communication structure Conficker uses. It has an algorithm to create a unique list of 250 random domain names every day. By precalcuting one of these domain names and registering it, the gang behind Conficker could take over any or all of the millions of computers they had infected.