Call it Conficker, Downadup or Kido - the fact is the nasty worm is spreading at a very rapid speed! There is no checking the pace at which it is infecting PCs; and with already more than 9 million victims, including corporate networks worldwide, the worm is still going strong!

The Downadup worm made its first appearance two months back, exploiting a critical Windows flaw in the way the Server Service handles RPC requests. A blended threat, the malware relies upon many attack vectors - from brute-force password guessing to hitching rides on USB sticks - for replicating itself to spread throughout a network.

The unique rate of speed at which the worm replicates has perplexed experts. Security researcher, Derek Brown, of TippingPoint's DVLabs Team, said: "The notion of using multiple attack vectors is not terribly new. The unique thing about this worm is the speed at which it has spread and I think that's a result of the big size of the Microsoft vulnerability."

Experts also opine that though the Downadup malware got started because of the Microsoft flaw, it later proliferated quickly through the unpatched Windows operating systems of the users.

Though the malicious worm knows no land barriers, the hardest hit countries, as per Symantec Security Response, are China and Argentina. According to the Symantec vice president, Alfred Huger, China accounts for almost 29 percent of the infections tracked, Argentina was next in line with over 11 percent infections.