RealNetworks has patched a vulnerability in its RealPlayer and HelixPlayer software that made it possible for attackers to run arbitrary code on a victim's machine. The security hole affects applications running on Windows, Mac and Linux platforms.

The vulnerability exists within the code that handles time formats for a feature in the applications that acts as a wall clock, according to iDefense Labs, which first discovered the flaw. An attacker can exploit the vulnerability by effecting a stack-based buffer overflow that allows for the execution of malware.

The gaping hole has been plugged, but you'd never know it from browsing the RealPlayer blog or the company's security advisories. That's unfortunate. Given the severity of the vulnerability, the updates - available here for RealPlayer and here for HelixPlayer - should be installed immediately.

RealNetworks spokesman Matt Graves said the lack of disclosure is the result of the company not knowing the iDefense advisory was going to be issued on Wednesday. The company is scrambling to add an advisory to its own website. (It is unclear if a messaging system within the applications warns users of the vulnerability.)

To exploit the flaw, an attacker would first have to prompt a user to open a specially crafted SMIL file. Simply luring a RealPlayer or HelixPlayer user to a booby-trapped website is sufficient for accomplishing this. SMIL files are written in an XML markup language that uses the Synchronized Multimedia Integration Language used to code things such as for timing, layout, animations, visual transitions, and media embedding.

The vulnerability has been confirmed in version 10 and 10.5-GOLD of RealPlayer for Windows, version 10 of RealPlayer for Mac, RealPlayer Enterprise and and HelixPlayer, an open source version of RealPlayer for Linux. Earlier versions of those programs are presumed susceptible as well, according to to iDefense. ®

Related stories

• High-priority patch fixes critical vulns in RealPlayer (25 July 2008)
• Unpatched RealPlayer bug paves way for drive-by downloads (12 March 2008)
• RealPlayer dinged by software watchdog group (31 January 2008)
• RealPlayer users warned over unpatched vuln (3 January 2008)
• IE + RealPlayer = Security hole (20 October 2007)
• Gentoo cuts key parts of itself from net for its own good (17 August 2007)
• Defcon A Defcon survival guide (1 August 2007)
• Apple TV gets its first critical security patch (20 June 2007)
• Apple plugs two QuickTime holes (30 May 2007)
• Apple patches security hole in QuickTime (2 May 2007)
• MySpace-hosted malware exploits QuickTime flaw (16 March 2007)
• Apple patches QuickTime bug (24 January 2007)
• Unpatched bug bites QuickTime (3 January 2007)
• Malware goes to the movies (16 November 2006)
• Media players hit by buffer overflow glitch (4 April 2003)
• RealPlayer security fix is faulty (26 November 2002)
• MS patches Media Player secure music vulnerability (27 June 2002)