Mac Hacked Via Safari Browser in Pwn-2-Own Contest

By Lisa Vaas  |  Posted 2007-04-20 Print this article Print

A zero-day vulnerability in Safari, the default browser for Apple's Macintosh operating system, allowed two MacBooks to crumble before the onslaught of a CanSecWest security conference attendee's hacking, aided as he was by a New York buddy with years of experience hacking Macs.

Shane Macaulay, a developer of binary security analysis tools, is going home with a 17-inch MacBook and sending $10,000 in prize money to his friend, Dino Dai Zovi. Dai Zovi told eWEEK in an interview from his apartment in New York that he was up since 10 p.m. on Thursday, following a phone call from Macaulay asking if he could help him in the CanSecWest Pwn-2-Own contest. By 7 a.m. he had the exploit in hand.

"I was up all night. I haven't slept yet," Dai Zovi said around 5:45 PST. "I sat down at 10 last night and by 7 a.m. I had a working vulnerability."

Dai Zovi said he "had some ideas" of where to attack. "I have my notes about what I've looked at, and what I haven't. I have little notes about something over here looking fishy, so check it out."

As a matter of fact, he investigated and reported to Apple a similar Safari vulnerability some two years ago.

Macaulay pwned the Mac by sending it an e-mail that directed a user to a malicious site. Upon visiting the site, the user—a CanSecWest organizer perched on the machine to protect it from physical assault—was infected with malware, without clicking on anything within the site.

On this, the last day of the security conference, none of the attendees had yet managed to convincingly molest the two laptops as of the morning. At first, the terms of the contest only stipulated that a remote attacker had to gain user access on a 15-inch MacBook or administrative privileges on a 17-inch MacBook.

On Thursday, TippingPoint sweetened the deal by pitching in $10,000 to hackers who manage to pwn the systems, in answer to hackers who shrugged off the idea of swapping a lucrative zero-day Apple vulnerability for a mere MacBook.

The value of such a vulnerability is reportedly around $20,000.

The MacBooks have been set up on their own Wi-Fi network, separate from that of the conference at large. The conference's Wi-Fi network has been suffering almost continuous denial-of-service attacks since the beginning of CanSecWest, with connectivity breaks coinciding mostly with morning hours before 10 a.m., before the bulk of hackers had managed to drag their (often hungover) bodies out of bed.

Dragos Uiri, the conference's M.C., announced on Friday morning that the contest had been opened to hackers to try their malicious Web page exploits against the systems. To do so they had only one new avenue opened to them: the ability to e-mail the machines at

"We first put the machines out, with the only option [being] to actively connect and try to remotely exploit [them]," said CanSecWest organizer Sean Comeau. "Nobody did it. So we expanded the attack surface by allowing them to send us e-mail. [Macaulay] supplied the URL."

The URL appears to lead to a blank page, but that's where the dirty work happened. Comeau described the hack as being similar to hacking Internet Explorer: With some IE flaws, all that has to happen is for a user to visit a Web site.

Macaulay was furiously typing away at his own Mac on a table adjacent to the Mac he was pwning when the successful hack was announced. He told a flock of reporters that the malicious Web site serving up the malware was not being hosted on his machine.

When answering questions while simultaneously typing at the keyboard, he would occasionally reach over to slap a plastic "Easy!" button from Staples.

"It was super easy," he said. [I used] client-side JavaScript, it does [code] execution, just arbitrarily executed a command, and that was it."

The rise of malicious JavaScript has actually been one of the hot topics at the conference this year, with Dr. Jose Nazario from Arbor Networks giving a presentation on the first day regarding how much more offensive and defensive JavaScript attack code has become.

Once he had gained access to the machine, Macaulay could escalate privileges via different paths, Comeau said, and of course could access any files on the machine with his local user access privileges.

The flaw for which Dai Zovi wrote an exploit exists solely in Safari, not in other browsers. Indeed, if the machine in the pwn-2-own contest had been running Vista, Macaulay wouldn't have bothered to try a remote IE exploit, he said.

"[IE flaws] are worth way more money—more people use them," he said.

Dai Zovi has been doing Mac research for awhile. Macaulay called him "the real center of research for the Popcorn frame." He wrote shell code for TCP for older generations and has written at least one wireless driver.

At that site, his bio reads as follows:

"I am a transient set of particles, constantly changing and exchanging some with everything that I come in contact with. Yet I ascribe some continuity and self-consciousness to the past, present and future of this amorphous being. This illusion engages daily in a megalomaniacal exercise, attempting to project the abstract into physical existence."

He told eWEEK that he's been working on Mac security in his spare time for about four years.

The $10 million question for both the hackers, of course, is an old one: Which is more secure, Windows or Macs?

That's the question I get hung with," Dai Zovi said. "My general sense is everything has vulnerabilities. There's nothing special about one platform that makes it impervious to vulnerabilities. Someone who knows what they're doing ... can find these vulnerabilities. Apple's been putting out [patches monthly for awhile]. Anybody who knows what's going on can develop exploits for these. There are many things the platform does security-wise that are somewhat better than Windows, but Windows has other security strengths, as well.

"I like Macs," he said. "I use Macs for everything."

Macaulay said he uses both, but on the whole he finds Macs "a little" more secure.

The hacking duo are firm believers in responsible disclosure: i.e., taking bugs to a software vendor before going public with them.

"We're trying to make computing more secure for everyone," Dai Zovi said. "Responsible disclosure is the best way to do that."

He said that he's found Apple "very responsive" to bug reports.

"Basically they reply within the day," he said. "The one thing they've tried to do, once they've fully investigated the issue is they'll let you know they're patching it now. Their stance is to take information, work with you to identify the cause, and converge it into the development process."

As for what he'll do with the $10,000 cash prize, Dai Zovi said he's thinking of buying a MacPro.

"I think Apple will get a large chunk of that money," he said. "It makes sense for them to fund themselves."

Depending on configuration, a MacPro can cost from $3,000 up to around $8,000. The balance of the funds will go toward drinks with friends, he said—what will constitute "ample celebrating" before he manages to get some sleep tonight.

"This was a great, fun exercise," he said. "I hope people are generally rational about these things. Vulnerabilities: You have them." |

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