Security firms are warning that a new strain of the Mydoom virus could spread more widely than its predecessor. They fear that the thousands of PCs infected by the first Mydoom bug are being used to spread the new variant. The second strain, called Mydoom.b, is programmed to attack the websites of Microsoft and software firm SCO. Microsoft has joined SCO in offering a $250,000 reward to find those behind what is now ranked as one of the largest virus outbreaks ever. At its height, Mydoom made up 30% of all e-mail traffic, according to anti-virus firms. The virus arrives as an e-mail attachment which sends itself out to other addresses if opened, and may allow unauthorised access to computers. It only affects computers using Microsoft Windows and also spreads through file-sharing networks, like Kazaa, installing a "backdoor" onto machines if launched. Anti-virus firm Kaspersky Labs said it fears that the backdoor installed on many machines is already being used to spread the new variant. You can find more discussion and the Mydoom Removal Tool here. Source: BBC News