The vulnerability lies in the Apple AirPort driver, according to details on the flaw published by H.D. Moore, the developer of the Metasploit security tool. It affects only the AirPort driver provided with wireless cards shipped between 1999 and 2003 with PowerBooks and iMacs, the posting said.
To launch an attempt, the hacker would have to be on the same wireless network as a vulnerable Mac. The attack entails trying to trigger a memory corruption flaw by sending a malformed data packet to the computer, according to Moore's advisory. But the process isn't easy, and Moore hasn't yet been able to gain complete control over a vulnerable Mac, he wrote in an e-mail to CNET News.com.
"The vulnerability itself only affects older hardware and is going to be difficult to turn into a remote code execution exploit, but it's definitely possible, just a matter of time and motivation," Moore said. "The current proof-of-concept triggers a fatal kernel panic and forces the user to power cycle their machine."
Apple is investigating the flaw, Lynn Fox, a spokeswoman for the Mac maker, said in a statement sent via e-mail. "This issue affects a small percentage of previous generation AirPort-enabled Macs and does not affect currently shipping or AirPort Extreme enabled Macs," she said.
The public release of the Mac vulnerability is the kick-off for an initiative titled the "Month of Kernel Bugs," launched by a security researcher who goes by the initials "LMH." As part of the effort, details of a new bug in low-level software will be made public every day. It is a follow-up to Moore's July month of browser bugs, and a jab at Apple's security and the company's response to earlier discussions of Wi-Fi flaws.
"With all the hype and buzz about the now infamous Apple wireless device-driver bugs, hopefully this will bring some light--better said, proof--about the existence of such flaws in the AirPort device drivers," LMH wrote on the Month of the Kernel Bugs blog.
In particular, LMH is referring to the widely publicized and often-criticized presentation on Wi-Fi driver flaws at a high-profile security conference. At Black Hat in Las Vegas, two security researchers showed how an attacker could gain complete control over a MacBook by sending malformed network traffic to a vulnerable computer.
At the time, Apple criticized the two for not proving their case. It came out with patches for Wi-Fi flaws a month later.
The Mac company handled that event poorly, Moore said. "I see this exploit as a great way to demonstrate just how easy some of the wireless driver vulnerabilities are," he said.
Moore's proof-of-concept exploit has been added to Metasploit Framework 3.0. This latest version of the security tool, popular with both security professionals and miscreants, has the ability to probe for vulnerabilities in wireless software.
"This allows Metasploit module developers to target all sorts of 802.11 wireless vulnerabilities," Moore said. "We plan on ramping up our 802.11 support over the coming months."
