The new Trojan can take over a PC and turn it into a “zombie” computer, but unlike regular zombie networks, the new threat causes spam to be sent through the mail server of each computer’s Internet service provider instead of simply turning the original computer into its own mail server.
Effectively, the new Trojan will cause problems with antispam filtering software that uses blacklists, because the mail will indicate it originates from an ISP’s mail server.
“The Trojan is able to order proxies to send spam upstream to the ISP,” SpamHaus director Steve Linford told ZDNet.
According to Linford, the threat is so dire that it could mean spam levels will rise from 75 percent of all email sent to around 95 percent of all email sent by the end of the year.
“We’ve seen a surge in spam coming from major ISPs,” Linford said. “Now all of the ISPs are having large amounts of spam going out from their mail servers.”
“The email infrastructure is beginning to fail,” Linford said. “You’ll see huge delays in email and servers collapsing. It’s the beginning of the email meltdown.”
Linford said that his warnings may fall on deaf ears, though, and he feels that ISPs may not have enough staff to be able to properly handle the problem.
“They’ve got to throttle the number of emails coming from ADSL account,” Linford said. “They are going to have to act quickly to clean incoming viruses. ISPs have so much spam – they are too understaffed to call people up and tell them they have Trojans on their machines. And no one would know what they’re talking about [if they did].”