XP

Nearly a month after a Google engineer released details of a new Windows XP flaw, criminals have dramatically ramped up online attacks that leverage the bug.

Microsoft reported Wednesday that it has now logged more than 10,000 attacks. "At first, we only saw legitimate researchers testing innocuous proof-of-concepts. Then, early on June 15th, the first real public exploits emerged," Microsoft said in a blog posting.

"Those initial exploits were targeted and fairly limited. In the past week, however, attacks have picked up."

The attacks, which are being launched from malicious Web pages, are concentrated in the U.S., Russia, Portugal, Germany and Brazil, Microsoft said.

PCs based in Russia and Portugal, in particular, are seeing a very high concentration of these attacks, Microsoft said.