For over 5 years, and perhaps even longer, servers around the world running Linux and BSD operating systems have been targeted by an individual or group that compromised them via a backdoor Trojan, then made them send out spam, ESET researchers have found. [Screenshot]
What's more, it seems that the spammers are connected with a software company called Yellsoft, which sells DirectMailer, a "system for automated e-mail distribution" that allows users to send out anonymous email.
This operation succeeded in remaining hidden for so long thanks to several factors: the sophistication of the malware used, its stealth and persistence, the fact the spammers aren't constantly infecting new machines, and that each of the infected machines wasn't made to blast out spam all the time.
Continued : http://www.net-security.org/malware_news.php?id=3030
Related :
Spam-blasting malware infects thousands of Linux and FreeBSD servers
Malware Discovered Targeting Web Servers Running Linux, FreeBSD

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