RealPlayer Exploit Infecting Windows Machines

By Lisa Vaas  |  Posted 2007-10-19 Print this article Print

No patches yet, but Symantec spells out mitigating strategies.

Attackers are exploiting a RealPlayer zero-day flaw to gain control of Windows systems through Internet Explorer, Symantec warned customers of its DeepSight Threat Analyst service late Oct. 18. The unpatched vulnerability affects all versions of RealPlayer, including the most recent, 10.5, as well as the beta of RealPlayer 11, Symantec told eWEEK. The zero-day vulnerability involves an ActiveX object in the RealPlayer component ierpplug.dll. Its not the first time this DLL has been exploited, but its the worst, given that only remote denial of service has been previously achieved.
"It appears that the miscreants have refined their technique to achieve code execution," Javier Santoyo, a manager at Symantec Security Response, said in a blog posting on Oct. 19.
The malware is being served on malicious Web sites. Santoyo told eWEEK in an interview that Symantec is unsure of how many sites are serving it up but that its a targeted attack against a Symantec customer. "Were not sure how the social engineering is being done" to get the customers employees to visit the rigged sites, he said. "I expect specific employees or groups are being sent e-mails. So the bad guys know which sites are being used more frequently by those [customers employees] and are targeting those sites." Click here to read more about Trojans targeting Skype. Santoyo was unable to say how many systems have been affected at the targeted company, but anybody who has RealPlayer installed could be at risk of exploit simply by visiting a malicious site; the player does not have to be running for the exploit to be successful. After a victim has been lured to a rigged site, the malware is checking the targeted PC to determine if the installed version of RealPlayer is vulnerable. The sample of code Symantec received, Trojan.Reapall, exploits the RealPlayer vulnerability and then downloads and executes a copy of a Trojan called Trojan.Zonebac. If so, an attacker can potentially take over the targeted system. Symantec said that if the vulnerability is successfully exploited, the malware triggers the playing of a clip called "videotest" from the "My Library" folder, available in standard installations of RealPlayer. Mitigating Strategies Until patches are available, Symantec offered these mitigating strategies:
  • Set the kill bit on the Class identifier (CLSID) FDC7A535-4070-4B92-A0EA-D9994BCC0DC5, (see instructions here.
  • Ensure that all Microsoft Internet Explorer clients are configured to prompt before executing Active Scripting. If Active Scripting is not required it should be disabled completely.
  • Configure all Microsoft Outlook and Outlook Express clients to either display all incoming email in plain text format, or ensure that HTML email is opened in the Restricted sites security zone.
  • Ensure that antivirus software is up to date. Symantec now has definitions that catch this malware.
  • Disable JavaScript whenever possible.
  • Always execute browser software as a user with minimal system privileges.
A spokesman for RealNetworks, maker of RealPlayer, told eWEEK that the company is currently investigating the vulnerability. He had no timeline for when a patch would be issued. Check out eWEEK.coms Security Center for the latest security news, reviews and analysis. And for insights on security coverage around the Web, take a look at eWEEKs Security Watch blog.
Lisa Vaas is News Editor/Operations for and also serves as editor of the Database topic center. Since 1995, she has also been a Webcast news show anchorperson and a reporter covering the IT industry. She has focused on customer relationship management technology, IT salaries and careers, effects of the H1-B visa on the technology workforce, wireless technology, security, and, most recently, databases and the technologies that touch upon them. Her articles have appeared in eWEEK's print edition, on, and in the startup IT magazine PC Connection. Prior to becoming a journalist, Vaas experienced an array of eye-opening careers, including driving a cab in Boston, photographing cranky babies in shopping malls, selling cameras, typography and computer training. She stopped a hair short of finishing an M.A. in English at the University of Massachusetts in Boston. She earned a B.S. in Communications from Emerson College. She runs two open-mic reading series in Boston and currently keeps bees in her home in Mashpee, Mass.

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