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Maynor reveals missing Apple flaw

And claims underhand play

Security researcher David Maynor got some measure of vindication at the Black Hat DC Conference this year. Six months after he and his colleague Jon Ellch claimed that Mac OS X wireless drivers were vulnerable to attack, Maynor on Wednesday revealed the code he used to exploit a native flaw in the platform as well as emails showing he notified Apple of the danger.

Maynor said the flaw was in the driver for the Broadcom wireless chip, the hardware under the hood of many MacBooks and PowerBooks.

In an email dated 9 August to Apple from his .Mac account, Maynor promised the company that his demo would not reveal the flaw in the native drivers, but in a third-party card, because the pair of researchers had not fully identified all the platforms affected by the Broadcom bug.

"Don't freak out," wrote Maynor, who is now the chief technology officer at startup Errata Security. "Although it is using a Mac, we are not sharing a native exploit. There are native exploits, but we are still determining how many other platforms are affected."

The flaw affected not only Mac OS X, but any platform that used drivers based on the Broadcom reference driver, he said. While MacBooks and PowerBooks were affected, so were Dell laptops running Windows XP. Apple fixed the flaw on September 21, but did not give Maynor or Ellch credit. The flaw could have allowed a remote attacker to compromise a vulnerable MacBook or PowerBook remotely via an overly long service set identifier (SSID), the label used to identify an access point.

Ellch was not present at the Black Hat DC Conference.

Apple did not immediately respond to requests for comment about the claims. However, in September, the company told reporters that the researchers did not send them information on the flaws, an assertion refuted by the email evidence shown by Maynor.

"They did not supply us with any information to allow us to identify a specific problem, so we initiated an internal audit," Apple spokesman, Anuj Nayar told Macworld. "Today's update preemptively strengthens our drivers against potential vulnerabilities, and while it addresses issues found internally by Apple, we are open to hearing from security researchers on how to improve security on the Mac."

The events underscored that the issues surrounding the disclosure of software flaws have not yet been hammered out. Apple has often been criticised by researchers for not working well with flaw finders.

The company is not the only one attempting to gag researchers: Another security researcher presenting on flaws in radio-frequency identification (RFID) proximity badges at the Black Hat DC Conference had to severely curtail his presentation, after security firm HID Global threatened possible legal action.

According to emails showed during Maynor's session, Apple's later assertions that he and Ellch shared no information with the company and that the researchers changed their story were both incorrect. On 15 August, Apple sent Maynor a blog entry to post on his site in his own name, disavowing the existence of any threat to Apple's laptops from the flaw, Maynor claimed. He showed an email from Apple to his .Mac account that supported the allegations.

Maynor and Ellch refused to talk about the issue because Apple had gagged the researchers by brandishing legal threats at Maynor's previous employer SecureWorks, the researcher said.

"Apple released patches, while at the same time threatening SecureWorks with a lawsuit," he said.

Apple likely made the mistakes out of a lack of experience in dealing with security issues, said Jeff Moss, director of the Black Hat Conference.

"It seems to be the new players who have no experience are causing the problems," Moss said. "Apple is where Microsoft was six years ago. At this point, they don't even have a CSO (chief security officer)."

For his part, Maynor plans to continue researching Apple flaws, but will no longer report the issues to the company.

"I no longer feel comfortable engaging in any type of relationship with the company and I will not report any future findings to them," Maynor said.

Maynor plans to post all of the documents and personal correspondence with Apple on Errata Security's blog.

This article originally appeared in Security Focus.

Copyright © 2007, SecurityFocus

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