Though the scheduled April 1 deadline for an update of Conficker worm came and went without much harm, the worm has recently released an update that could trigger the botnet for transporting spam and turning infected PCs into automatons.

Analysts opine that the newly-released strain of the Conficker C updates the already-infected machines, using peer-to-peer techniques for distribution. At the same time, researchers also say that the new sample does not apparently include new infection vectors either for swifter dissemination or for hitting new machines.

According to researchers, the new Conficker update possibly includes a correlation involving the Conficker worm and the active spam bot W32.Waledac. In particular, the available incidental data reveals that the updates might drop a Waledac binary on the Conficker C-affected machines. 

Experts say that the binary is so-designed that it can facilitate information stealing, thereby converting the infected machines into spam-spewing drones controlled by the malware authors. However, the strain would eliminate itself from infected PCs on May 3, and hit out to newer high-profile domains.

Talking about the new Conficker strain and its targets, Vincent Weafer, VP of Symantec Security, said: “We got a first look at the payload and we're still looking at this one, a worm called Waledac associated with tons of spam. Ultimately it's about information stealing.”