Security experts are warning of a Trojan horse that can
automatically attach spam to emails, instant messages and bulletin
board postings.
Symantec
researcher Eric Chien said that the malware uses a Windows layered
service provider component to watch network traffic and alter
outgoing messages and posts.
"Message board spam is nothing new," Chien explained on the
company's security response blog. "But what is different about this
message board spam is that the spam text is integrated into
legitimate messages posted by real users. "
The attack begins when a user follows a link posted on a spam
message or posting promising a 'funny video'. The user is then
tricked into downloading an executable that installs the Trojan,
formally known as Trojan.Mespam.
The malware will attach the spam greeting to message board postings
as well as instant messages sent from AIM, Yahoo Messenger, GTalkand [www.icq.com]
ICQ[/url].
Chien said that emails sent from most popular webmail services,
including Google
Mail, Hotmail and Yahoo Mail, will also be injected with
spam code.
The researcher recommends users to avoid clicking on unrelated
links in forum postings, emails and instant messages, and to avoid
executing any unsolicited files from a suspicious source.