Researchers at Core Security have released details of three vulnerabilities in Apple iCal scheduling application, after four months of talks with the company.
The security tools vendor said it is important for users to know about the flaws and make security precautions, even without a patch from Apple.
The iCal bugs comprise a single memory corruption flaw and two null-pointer vulnerabilities. The memory corruption bug creates a mechanism for attackers to inject hostile code into affected systems. The null pointer bugs might be used to crash the scheduling program.
Each flaws stems from a failure by Apple software to sanitize part fields within iCal calendar files (.ics). iCal versions 3.01 and 3.02 (the current version) are vulnerable.
The application comes bundled with Mac OS X, so many Apple users are at risk.
There are two possible exploits:
- Send maliciously constructed electronic calendar updates to iCal users
- Trick users into importing malformed calendar files from a website under the control of hackers
There's no evidence that black hats have launched attacks based on the flaws, but the opportunity for mischief remains.
In the absence of a patch, the workaround is DON'T. Don't apply calendar updates and Don't accept files from untrusted sources.
Waiting for Godot
Core researchers discovered the flaws in January 2008. Since then they have worked with the vendor through a long and protracted series of exchanges, as detailed in an advisory on BugTraq here. The inconclusive argument revolved around whether the bugs were serious enough to patch and, if so, when Apple would issue patches.
Eventually Core said it would publish an advisory on Wednesday (21 May) in the belief Apple was ready to release a fix on Monday (19 May). In the event this patch failed to appear, and is still missing in action two days later.
Ivan Arce, CTO of Core security, confirmed that no patch had been released for the iCal vulnerabilities by Thursday afternoon. Apple released fixes for a WikiServer vulnerability – notified to it by Core Security at the same time as the iCal bugs – back in February.
iCal comes bundled with Mac OS X. Arce was reluctant to speculate as to why the iCal fixes had taken so long to develop, but suggested that testing might account for the delay.
Apple has a factious relationship with some security researchers. But Arce found the consumer electronics giant no better or worse than many vendors he deals with.
“I don't think its response any worse," he said. "Apple's security team was proactive in responding to us and came back with analysis on the impact of the flaw. We didn't intend to release an advisory before it but we think it was important to get the information out so that people can know how to protect themselves."
“Apple postponed the release of a patch many times," he added. "I think this is more to do more to do with its internal process, and the need to do regression testing, than complexity of the flaws.” ®