An independent security researcher on Tuesday posted an advisory—with zero-day exploit code—for a potentially dangerous security hole in media players marketed by RealNetworks Inc.
The vulnerability, which remains unpatched, has been confirmed in RealPlayer version 10.0.5.756 (gold) and affects only the Linux/Unix platforms.
Security alerts aggregator Secunia Inc. rates the bug as "highly critical" and warned that a malicious hacker could run a successful exploit to take complete control of a vulnerable machine.
The vulnerability was discovered and reported to RealNetworks by a researcher known simply as "c0ntex."
In a warning posted to the Open-Security Web site, the researcher described the issue as a "remotely exploitable format string vulnerability" that allows an attacker to "execute a remote shell under the permissions of the user running the media player."
He said the bug affects all versions of RealPlayer and Helix Player (Unix and Linux) and can be exploited by manipulating media files, including ".rp" (RealPix) and ".rt" (RealText) file formats.
In the advisory, "c0ntex" provides a detailed explanation of the flaw and code that can be used to launch an attack. The exploit code was reproduced at FrSIRT (French Security Incident Response Team), a Web site that is widely used by underground hackers.
"To exploit this remotely, [an attacker] just needs to place the created file on a Web site and provide a link so users can click the file, launching RealPlayer and exploiting the vulnerability," he added.
Software vendors, including big names like Microsoft Corp. and Oracle Corp., have sharply criticized third-party hackers who release flaw warnings and zero-day proof-of-concept exploits, insisting that the practice puts users at risk of attack.
In this case, "c0ntex" said he was working privately with RealNetworks on a patch but decided to release the exploit to prevent someone from stealing his work.
"[I]t seems someone is trying to pinch my research, as such I have been forced to release this advisory sooner than hoped. Until [RealNetworks can] get a new release out, do not play untrusted media with RealPlayer or Helix Player," the researcher said.
He even added an apology to the Seattle-based digital media delivery company.
This is not the only unpatched flaw in the RealPlayer software. eEye Digital Securitys list of upcoming advisories includes two high-risk vulnerabilities in the widely deployed media player.
According to eEye, RealNetworks has been working on a fix since early July. Both flaws could open the door for malicious code execution attacks.