tsu doh nimh writes: Authorities in Europe joined Microsoft Corp. this week in disrupting "ZeroAccess," a vast botnet that has enslaved more than two million PCs with malicious software in an elaborate and lucrative scheme to defraud online advertisers. KrebsOnSecurity.com writes that it remains unclear how much this coordinated action will impact the operations of ZeroAccess over the long term, but for now the PCs infected with the malware remain infected and awaiting new instructions. ZeroAccess employs a peer-to-peer (P2P) architecture in which new instructions and payloads are distributed from one infected host to another. The actions this week appear to have targeted the servers that deliver a specific component of ZeroAccess that gives infected systems new instructions on how to defraud various online advertisers, including Microsoft. While this effort will not disable the ZeroAccess botnet (the infected systems will likely remain infected), it should allow Microsoft to determine which online affiliates and publishers are associated with the miscreants behind ZeroAccess, since those publishers will have stopped sending traffic directly after the takedown occurred. Europol has a released a statement on this action, and Microsoft has published a large number of documents related to its John Doe lawsuits intended to unmask the botnet the ZeroAccess operators and shut down the botnet.