If you use Internet Explorer (versions 6 or 7) to browse the Web, listen up: Criminals are starting to exploit security holes in several widely installed IE plug-ins to plant invasive software when users are coerced or tricked into visiting one of several Web sites. In an alert posted Friday evening, security software vendor Symantec said it is seeing malicious Web sites popping up trying to exploit vulnerabilities in a set of ActiveX controls produced by Aurigma, a technology company whose image transfer browser plug-in is licensed and distributed by a number of major Web sites to help IE users upload pictures. Currently, Facebook.com and MySpace.com are among the biggest distributors of this ActiveX plug-in, but they are hardly the only ones. Symantec warns that if visitors don’t have the Aurigma plug-ins installed, the sites will probe for other vulnerable IE plug-ins, including two recently discovered from Yahoo! and one