1 of 3 Windows computers are vulnerable to worm

According to Qualys Inc. about 30% of the machines have not yet been patched with the "out of cycle" fix Microsoft provided Oct. 23 as security update MS08-067.

Nearly a third of all Windows systems remain unpatched 80 days after Microsoft rolled out an emergency fix for the Downadup worm.

Based on scans of several hundred thousand customer-owned Windows PCs, Qualys Inc concluded that "The unpatched numbers went down significantly around the 30-day mark," said Wolfgang Kandek, Qualys' chief technology officer, "when less than 50% were unpatched. After that, it went down a little slower. As of yesterday, 30% of the machines are unpatched."

With nearly a third of all Windows systems still vulnerable, it's no surprise that the "Downadup" worm has been able to score such a success, Kandek said. "These slow [corporate] patch cycles are simply not acceptable," he said. "They lead directly to these high-infection rates."