We've been monitoring for active attacks on the Windows Help and Support Center vulnerability (CVE-2010-1885) since the advisory was released on June 10th. At first, we only saw legitimate researchers testing innocuous proof-of-concepts. Then, early on June 15th, the first real public exploits emerged. Those initial exploits were targeted and fairly limited. In the past week, however, attacks have picked up and are no longer limited to specific geographies or targets, and we would like to ensure that customers are aware of this broader distribution. If you have not yet considered the countermeasures listed in the Microsoft Security Advisory (2219475), you should consider them.
As of today, over 10,000 distinct computers have reported seeing this attack at least one time.
Update from Microsoft
First seen in the wild Story @ The Register