GFI Software announced it is tracking a new method through which <A HREF="http://www.gfi.com/news/en/mp3spam.htm">spammers send messages with MP3 attachments</A> that contain the latest pump-and-dump stock scams. The spam is a short, 30-second MP3 file recorded at low bit-rate with a synthetic female voice promoting a particular stock; the voice heavily distorted to avoid signature-based anti-spam approaches.
Spammers are taking advantage of the fact that the MP3 format is one of the most common in use today and that most anti-spam solutions do not handle attachments very well because they do not actually analyze the attachment content. To address the MP3 spam threat administrators need to deploy as many anti-spam techniques as possible, including Bayesian filtering, while at the same time maintaining a very low level of false positives. Additionally, administrators can block attachments or place restrictions on allowable sizes to weed out unwanted material.