Apple is hanging tough to maintain market leadership in digital music.

The company is ready to exploit any weakness betrayed by its competitors - as it surely expects they will against it.

Since Napster launched Napster To Go, a group of hackers have already managed to build an exploit to undermine the Microsoft digital rights management in the tracks.

Apple CEO Steve Jobs learned of this, and seized the opportunity to cast aspersions against Apple's rivals, the LA Times reports he, "sent an email Tuesday morning to top record industry executives", which warned them of Napster's DRM disappointment.

"Thought you should know if you haven't heard about this" he allegedly told them, helpfully directing the music industry to a page where they could download the copyright-crashing software to undermine Napster.

Now in damage control mode, Napster CEO Chris Gorog responded that such hacks weren't unique to Napster, and offered label execs the name and address of a hack designed to undermine Apple's digital rights management.

Not Apple, nor Napster, nor the labels chose to comment on the LA Times story.