Researchers make Mac OS X worm

Identified only as the researcher behind the Information Security Sell Out blog, he or she on Sunday announced that a still-unpatched bug in mDNSResponder, a component of Apple's Bonjour automatic network configuring service, could be exploited by a worm. Apple's May security update, dubbed 2007-005, included a fix for the mDNS bug.

"[My worm] is in the same code base, obviously, but that is where the similarity to the recently patched issues ends," said the Info Sec researcher in an e-mail interview. "When Apple fixed the previous issues, they did not take care of the entire code base and there are a lot of bugs there...some are exploitable, like the one I am using, while others are not. But the fact remains that Apple did a horrible job in fixing this package."

According to Info Sec, the worm is fully automated and ready to use. "It would be considered a fully weaponized exploit and fully automated," said the researcher. "This is really no different than other worms we have seen [on the Windows platform]. Other than that, I am not able to give any more details."

Another researcher, however, questioned whether Info Sec crafted the worm in only a few hours, as claimed. "Writing the exploit in one day...unlikely for anything other than a stack overflow," said Dave Aitel, the chief technology officer at Immunity Inc., the Miami Beach, Fla.-based security company best known for its CANVAS penetration testing ("pentest") software. "So most likely he found a stack overflow in mDNS, which is perfectly possible. It is open source, after all."