World's most sophisticated Trojan

Security experts have discovered new spambot software that installs its own anti-virus scanner to eliminate competition, alongside a number of other sophisticated features.

SecureWorks has described the Trojan, which it calls SpamThru, in detail. Others vendors have come up with different names for the software. One of the signs of its sophistication though is that few anti-virus scanners are aware of it, SecureWorks said.

"SpamThru is a money-making operation, and the author takes great care to make sure that detection by the major vendors is avoided by frequently updating the code," said SecureWorks' Joe Stewart in the company's analysis.