According to a senior security researcher at SecureWorks, the bot-netters grew their 70,000 strong zombie network with the SpamThru trojan, an innovative piece of malware which not only packs its own pirated version of Kaspersky Anti-Virus to eradicate any competing malware from infected computers, but also uses a list of proxy servers to evade blacklisting by anti-spam agencies.

The researcher also claims to have uncovered evidence that the spammers harvested lists of email addresses from financial institutions:

It also appears the spammer made an effort to obtain more targeted lists of email addresses by hacking into smaller investment news Web sites and other e-businesses and downloading their user databases,” he said. “This is likely due to the fact that pump-and-dump stock spam seems to be a primary motive of the botnet.

Mail.app users can get some level of protection by creating a rule to filter some of these images spams out.

David Reitter takes a slightly different approach with a different rule.

Fastmail users (and others with tweakable server-side spam protection) may get some extra relief from this tip on EmailDiscussions.com which creates a more sophisticated rule.

[Via Daring Fireball ]mail.app, apple mail, image spam, junk, rules, email, bot-net, trojanSimilar Posts:

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