6 percent of PCs hit by Downadup worm

According to Panda Security, almost 6% of the Windows systems scanned with its antivirus technology were found to be infected with "Downadup," a worm that began aggressive attacks just over a week ago. Panda was one of the first security firms to sound an alarm over Downadup when it raised its security threat level on Jan. 12 as reports of attacks mounted.

Using data from antivirus scans performed by its consumer-grade security software and by a free online scanning tool that it makes available on its Web site, Panda found 111,379 PCs infected with the worm out of a pool of 2 million machines.

"I'm pretty confident in this number," said Ryan Sherstobitoff, chief corporate evangelist at Panda Security, as he cautioned it was just a snapshot. "Conficker is still infecting high volumes of machines and is a fast-propagating worm."

Conficker is an alternate name for the Downadup worm.