Surprised researchers have discovered that MP3 spam has returned. It was last seen in 2007 and like PDF spam, was thought to have been discarded by spammers in favor of simple link spam. However, late last week security researchers discovered a brand new spam campaign using MP3 attachments. The MP3 was of a computerized voice hawking the website of a fake Canadian pharmacy that offers shady male enhancement pills and Viagra, with the audio from Meg Ryan’s famous scene in “When Harry Met Sally” playing in the background. There were random characters in the lyrics tag, an attempt to evade spam detectors that work by noting MD5 file hashes.

The campaign lasted just 24 hours but sent out over 500 million messages, accounting for 1.2% of the global spam volume for that time period. It’s believed that the Cimbot botnet is responsible for the spam. It boasts a network of between 10,000 and 20,000 zombies, most which are located in Europe. Cimbot had previously launched an image spam campaign hawking the same products and leading to the same Canadian pharmacy website.