This vulnerability was reported earlier here--- http://www.bleepingcomputer.com/forums/t/323750/windows-xp-unpactched-vulnerability/
QUOTE FROM LINK ABOVE:
Hi-tech criminals are "escalating" attacks on an unpatched bug in the Windows XP help and support system.
Microsoft said it had seen more than 10,000 machines hit by the attack that, so far, it has not found a fix for.
...A variety of trojans, spam tools and viruses are being downloaded to compromised machines....
........Statistics gathered by Microsoft suggest Portugal was taking the brunt of the attacks but users in Russia and Croatia were also being hit. More than 10,000 machines had been hit at least once by the attack, it found.
To avoid falling victim, Microsoft advised users to turn off the part of the Help and Support system that is vulnerable. It has produced an automated tool that can do this for users.
Microsoft said it was working on a lasting fix for the loophole.
How to disable the HCP protocol using the automated Fix It tool : http://support.microsoft.com/kb/2219475