KaZaA, the media desktop, has been one of the most successful replacements for file sharing, allowing its users a way of sharing music, video, documents, images, and software.
But six per cent of all music downloaded from KaZaA is not music at all, but a virus. Currently, there is no way to infect mp3s with a virus; however KaZaA"s poor filtering allows someone to rename a virus to - say - cant_touch_this.mp3.vbs. When you do a search for the song named "Can"t Touch This" KazaA will display this as "cant_touch_this.mp3", without displaying the .vbs extension.
This problem affects more than music: Hacker"s Digest Labs has found the Love Letter Virus disguise as videos, images and executables.
What does KaZaA say about this? This is what the FAQ has to say:
Q: Can I get viruses using KaZaA?
A: As always when you are downloading or receiving files from the Internet, you must exercise caution. You should protect yourself by using regularly updated anti-virus software. You should also be cautious of executable files (.exe) and Microsoft Word and Excel documents (.doc and .xls). These files are specified with a "!" icon in the search results on KaZaA.com.
This is true, however with the poor filtering in the KaZaA media desktop, it is extremely easy for anyone to be tricked into running a virus thinking it is his or her favorite song.
Final note: this applies to Morpheus and a couple of other sharing systems.