Symantec's Norton AntiVirus line has a pair of vulnerabilities that hackers could exploit to crash or hang a targeted PC, Symantec announced Monday.

The Cupertino, Calif.-based security company's consumer AntiVirus 2004 and AntiVirus 2005 series are at risk, said Symantec, as well as the Internet Security and SystemWorks lines, which bundle AntiVirus with other security or PC maintenance tools.

Errors can be forced, said Symantec, by attackers feeding specific file types to a machine protected by AntiVirus' Auto-Protect module, or by renaming a file on a network share that's then scanned by Auto-Protect. (Auto-Protect is Symantec's name for the real-time scanner that sniffs through files as they're opened or downloaded.)

The errors can cause the PC to either slow down to the point of being unusable, then crash, or hang, forcing its user to reboot.

Symantec has issued patches for the vulnerabilities and has already fed them to AntiVirus users who have Automatic LiveUpdate enabled. Others should run LiveUpdate immediately from within their copies of Norton AntiVirus.

Symantec posted a security alert on its Web site with more details.