In late October Sony was found to be using stealth techniques to hide software that stopped some of its CDs being illegally copied.

Now three virus variants have been found that use the Sony software to evade detection by anti-virus programs.

I think it's actually one virus that goes by three different names, rather than three different viruses.

In the same article is this from Sony.

In response to the concerns, Sony has released a statement "deeply regretting any disruption that this may have caused." It added that it would work with anti-virus firms to ensure its anti-piracy system stayed safe.

Which makes me wonder what exactly they mean about keeping the anti-piracy system safe - For the end user, or from the anti-virus programs...