Researchers predicted that exploits would quickly follow the discovery of a vulnerability in how QuickTime handles RTSP responses from a video/audio streaming server, and they were right: Three have been publicly posted, one of which is in an "almost weaponized state," according to Errata Security Chief Technology Officer and founder Dave Maynor.
The three exploits were posted on the Milw0rm public forum between Nov. 24 and 27, with the most recent and most dangerous put up by a poster named Yag Kohha on Nov. 27.
"This means that anklebitters, bot masters and a general assortment of unsavory types now have everything needed to easily take advantage of the flaw," Maynor said in a Nov. 27 posting.
The exploits target Windows, but Maynor warned that Apple users should also be wary, given that the flaw is present in Mac OS X.
Errata has received word that the exploits are showing up in the wild but had not validated those reports as of Nov. 27.
The exploits work by sending a malformed RTSP (Real Time Streaming Protocol) response header that allows shell code to be executed on a victims machine.
Trend Micro TrendLabs Rommel Garcia said in a Nov. 28 posting that another way to exploit the flaw is for an attacker to set up a Web site that contains script or malware objects that direct RTSP connections to a malicious remote server.
Maynor said in his posting that, following a Symantec posting to the effect that standard buffer overflow protection may mitigate the vulnerability, one of the proof-of-concept exploits has been tweaked to work via a redirection attack on Internet Explorer 7, Firefox and Opera. Maynor said that Safari on Windows was apparently left out of the exploits list of targets, but that doesnt necessarily mean it is safe to use.
TrendLabs is recommending that users stay away from unknown sites or those sent from unknown sources. Another mitigation strategy is to block connections coming through port 554—its at this port that at least one of the exploits listens, waiting to send a response with a maliciously crafted RTSP header.
But as US-CERT mentions in its mitigation strategies, its possible that RTSP uses other ports as well, so blocking the protocol based on that particular port might not provide protection. Also, there is always the option of removing QuickTime completely until a patch is available, Maynor said.
Apple has not responded to questions regarding when a patch will be available.
Researchers are blaming Apple for this fiasco, given that the company neglected to enable QuickTime to take advantage of ASLR (address space layout randomization). ASLR, a technique that prevents an attacker from being able to easily predict target addresses, could have mitigated attacks by changing the load address of components to render the attacks merely denial-of-service, Maynor said.
"If Apple had enabled QuickTime to take advantage of ASLR in all of its components, this would be a non-issue. Instead they put you at risk," he said.
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