PCs that have been compromised by Trojans are being used by spammers to relay vast amounts of email and avoid detection
One third of all spam circulating the Web is relayed through PCs that have been compromised by Remote Access Trojans (RATs), according to corporate spam and antivirus company, Sophos.
Cluley said that if a RAT is able to get into a PC, an attacker could take full control of that PC, as long as it is connected to the Internet. "They can steal information, read files, write files, send emails from that users name -- it is as though the attacker has broken into the office or home and is sitting in front of that computer," he said.
http://news.zdnet.co.uk/communications/broadband/0,39020342,39118252,00.htm

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