Researchers at eEye Digital Security, the company that discovered the flaw, said it could be exploited by remote hackers to take complete control of the target machine "without any user action."
"This is definitely wormable. Once exploited, you get a command shell that gives you complete access to the machine. You can remove, edit or destroy files at will," said eEye Digital Security spokesperson Mike Puterbaugh.
"We have confirmed that an attacker can execute code without the user clicking or opening anything," Puterbaugh said.
eEye, based in Aliso Viejo, Calif., posted a brief advisory to raise the alarm about the bug, which can allow the execution of malicious code with system-level access. The flaw carries a "high risk" rating because of the potential for serious damage, Puterbaugh said.
Symantec, of Cupertino, Calif., confirmed receipt of eEyes warning and said an investigation was underway.
"[Our] product security team has been notified of a suspected issue in Symantec AntiVirus 10.x. [We] are evaluating the issue now and, if necessary, will provide a prompt response and solution," a Symantec spokesperson said in a statement sent to eWEEK.
Symantecs anti-virus software is deployed on more than 200 million systems in both the enterprise and consumer markets, and the threat of a network worm attack is very real. However, eEyes Puterbaugh said there are no publicly shared proof-of-concept exploits or other information to suggest an attack is imminent.
But, he said, "theres nothing to say that someone hasnt found this and is already using it for nefarious activities. … Its quite possible that we werent the only ones to find this. Who knows if its already being used in targeted attacks that well never hear about."
Internet security experts have long warned that flaws in anti-virus products will become a big target for malicious hackers. During the last 18 months, some of the biggest names in the anti-virus business have shipped critical software updates to cover code execution holes, prompting speculation among industry watchers that its only a matter of time before a malicious hacker is motivated to create a devastating network worm using security software flaws as the attack vector.
"The big surprise is we havent seen one yet," said Johannes Ullrich, chief technology officer at the SANS ISC (Internet Storm Center), of Bethesda, Md., in a recent eWEEK interview.
In March 2004, the fast-moving Witty worm exploited a zero-day buffer overflow in security products sold by Internet Security Systems. Unlike most self-propagating worms, Witty was capable of corrupting the hard drives of infected machines, preventing normal operation of the PC and eventually causing it to crash.
"This could be Symantecs Witty," Puterbaugh warned.
The vulnerable Symantec 10.x application promises real-time detection and repairs for spyware, adware, viruses and other malicious intrusions. It is used by many of the worlds largest corporate customers and U.S. government agencies.