A wave of spam in the form of MP3 files posing as music clips is now circulating, security experts have warned.
This is the first time that spam hiding inside sound files has been circulated on a large scale, said web security company MessageLabs.
The MessageLabs Intelligence Report for October reveals that spammers have sent at least 15 million emails so far in the form of MP3 music files, as they seek to expand the ways spam can be propagated.
The report said this first run of MP3 spam used computers infected with the StormWorm virus to disseminate the emails. The malicious mails had a variety of music-related file names such as beatles.mp3, britney.mp3 and elvis.mp3, and contained a 25 second voice-over from an organisation called Exit Only Incorporated, it has reported.
Spammers have been trying different types of file attachments including text, html, image, ZIP, RAR, RTF and PDFs in recent months, commented Mark Sunner, chief security analyst for MessageLabs.
"The MP3 spam tactic is a natural progression for cyber criminals following runs of image, PDF and Excel junk mail earlier this year," he said. "As users become wary of certain file attachments, scammers will move on to their next tactic, ever hopeful of finding the key which will easily open all inboxes rather than having the door slammed in their face by anti-spam filters. Video spam and PowerPoint are both well anticipated so watch this space for the next format du jour."
This recent trend, he said, proves that spamming techniques are becoming more innovative. He predicted that it is only a matter of time before spammers upload malware to free multimedia hosting sites such as YouTube, Google Video or MySpace.
"It's not just the spammers that are trying to latch onto trends and internet user habits," said Mike Greene, vice president of product strategy at security software firm PC Tools. "We are seeing increased malware traffic via some of the less scrupulous MP3 download sites in areas such as Russia, as well as MP3 and video sharing sites across other regions. Users have to be more vigilant and adopt a less trigger-happy approach to web browsing and start treating unusual and unsolicited emails with greater suspicion."
