At first blush, the past two weeks have not been good for the image of Apple's Mac OS X: Public descriptions of two worms and a trivial exploit for a serious software issue in the operating system appeared on the internet.
However, the three programs are hardly a threat to systems running Mac OS X, according to security professionals.
One worm, known as OSX.Leap.A and assigned CME-4 by the Common Malware Enumeration Project, requires too much user interaction, hobbling its attempts to spread. A second worm, dubbed InqTana, and its two variants are actually proof-of-concept programs that were not discovered on the internet but were instead sent to anti-virus vendors and Apple by a researcher to prove that worms can spread through Bluetooth. And while the release of code for a vulnerability that could be exploited through Safari and Mail is a bit more serious, no incidents of websites exploiting the flaw have yet been reported.
"I don't think what we've seen is serious at all from the end-user perspective," said Mikael Albrecht, product manager with anti-virus firm F-Secure. He added that the issues the programs use to attempt to spread could result in more serious attacks, however. "From the security perspective, the vulnerabilities are quite severe."
The largely ineffectual attacks add fuel to the fiery debate over the security of Apple's operating system. Many Mac users believe they are better protected than the average Windows user against malicious attacks. Most security professionals argue that, as flaw finders scrutinise the increasingly popular operating system, more vulnerabilities will be found, and Mac users will have to deal with many of the threats that worry Windows users.
In the latest security issue for Mac OS X, a vulnerability in how the operating system uses meta data to associate file types with programs could be exploited to allow a Mac to be compromised through web browsing or via an email message, according to flaw finder Michael Lehn, a graduate student and researcher in the University of Ulm's Department of Numerical Analysis. The researcher recently discovered the vulnerability and reported it to Apple.
Because of the severity of the flaw, and the possibility that someone else had found it - Apple lists the flaw as a duplicate in its bug database - Lehn opted to release details of the vulnerability and proof-of-concept code, a move he said helps Mac users. However, the move violates generally accepted responsible disclosure guidelines.
"Because of the first worm, too many people were suddenly starting to think about and investigate the possibility of writing a Mac OS X worm," Lehn said. "Publishing the exploit as fast as possible is the best for all Apple users. I think at the end of the week, every Apple user will know about it."
Without advanced notification, Apple is currently scrambling to release a patch for the issue, which has not yet been encountered by users on the internet.
"Apple takes security very seriously," an Apple spokesperson told SecurityFocus. "We're working on a fix so that this doesn't become something that could affect customers."
The company added that Mac users should only accept files from the software developers and websites that they know and trust.
The InqTana worm, created by security researcher Kevin Finisterre of Digital Munitions, held to responsible disclosure but runs counter to many anti-virus vendors' assertions that creating viruses and worms is not an acceptable security practice. Finisterre created the InqTana worm, and two variants, to show that a worm could spread through Macs. Each variant uses a different method to copy itself onto a computer running Mac OS X.
However, Finisterre designed the worms not to spread in general. The programs made use of a vulnerability found and reported by Finisterre and fixed by Apple last June. The researcher also hobbled the worm by requiring that a user agree to allow the program to spread to their computer, and placed a time limit on how long it could spread. Moreover, he only sent the program to security contacts at Apple, major anti-virus companies and a single independent security group.
"I have heard of so many folks touting that misconception that Macs can't get viruses that I thought it was about time to start a dialog with some of the AV companies and express some of my ideas," Finisterre said. "In the process of confirming my own concerns, this code was created. I am not one for talking about things in concept form - I like to actually implement and prove a concept."
While InqTana is not a danger, Finisterre stressed that Mac users need to wake up to the fact that successful worms and viruses will attempt to attack the Mac OS X in the future. The poorly programmed OSX.Leap.A also shows that malicious coders are focusing on the platform, he said.
"The idea that Macs can't get viruses is simply absurd and I wanted to highlight that fact," Finisterre said. "It was pure coincidence that Leap.A had already set out to prove that the old wives' tale is false."
F-Secure's Albrecht stressed that worms are not a good way to demonstrate vulnerabilities, but that the two programs, despite their lack of success, do show that viruses and worms are a threat for the platform.
"I would never want to say releasing a virus is a good idea, but the worms for the Mac OS X are a wake up call for the community and that is a good thing," Albrecht said. (Symantec, a rival to F-Secure in the anti-virus industry, is the owner of SecurityFocus.)
The two worms and the exploit could also give would-be malicious coders encouragement in their attempts to create programs for the Mac OS X platform, Internet Security Systems director of intelligence Peter Allor said.
"It's like going through the sound barrier. People think you can't go through the sound barrier and then someone does it and suddenly people know it's possible. It doesn't mean that people are going through the sound barrier every day, but they know they can."
While many Mac users are cognizant of security risks, others - oft-times referred to as the "Mac Faithful" - take umbrage at what security professionals regard as common-sense security precautions, said Jay Beale, senior security consultant with Intelguardians and leader of the Bastille Linux Project.
Mac users should take the convergence of the three threats as a signal to inspect their defenses against online attacks, he said.
"We Mac users have been living in this great world where we are more vulnerable than other Unixes, but we weren't seeing any attacks because we weren't targeted," Beale said. "I think we are going to see a lot more of this in the next year."
In addition, Apple needs to shake off its secretive approach to security and communicate better with the community and security researchers, Finisterre said. The researcher said that his attempts to communicate with the security response team at Apple has been mixed.
"Macs will continue to attract attention, and by doing so, we are going to see a lot of creative attacks come out," Finisterre said. "The ultimate outcome is in Apple's hands - how they respond both proactively and reactively will make all the difference."
This article originally appeared in Security Focus.
Copyright © 2006, SecurityFocus