F-Secure has received a sample submission of a virus for iPods running on Linux, showing that "the computer underground is actively studying new platforms such as portable devices," according to Chief Research Officer Mikko Hyppönen.

The virus, sent to F-Secure in a .zip file called Oslo, doesn't work on iPods running the default iPod operating system. Hyppönen said in a blog entry that the virus wasn't able to replicate on any operating system except Linux.

iPod Linux is a µCLinux-based software distribution targeted specifically to run on Apple iPods. It allows users to play games including Doom and Doom II, games for the Nintendo Game Boy, and the Tetris clone Bluecube. It also allows for much higher-quality recording than Apple's firmware through the iPod's audio jack, and it provides emulators such as iBoy for Gameboy and iNES for Nintendo Entertainment System Emulator.

F-Secure notes that iPod Linux is a rare operating system and that this virus is at this point only a proof of concept. Although it's not going to become a real-world problem, Hyppönen says, it shows that there are people out there trying to figure out how to exploit portable devices.

"And it really is theoretical," he writes. F-Secure installed iPod Linux on some iPods but couldn't manage to get the malware up and running correctly.

Kaspersky, however, did, after having to deal with bugs in the virus that crash the system with Linux debug messages.

Kasperky's blog shows an infected iPod displaying a penguin wearing ear buds, holding an iPod and waving. A message reads, "Oslo Virus: You are infected with Oslo, the first iPod Linux Virus by freeOn/DoomRiderz."

Kaspersky dismissed the potential impact of the virus sample, given that users don't often download new applications or other files. Eugene Kaspersky wrote in the blog that the virus is an "interesting little puzzle ... but nothing more."

"Overall, I don't think iViruses will cause serious problems in the future," he said. "The iPod world is very different from the PC and smartphone world. Users aren't constantly installing new software and downloading a wide range of files, so that cuts down on the possible infection vectors. And what's there to steal from an iPod? Multimedia files, and that's about all."