Symantec unveiled on Feb. 28 a free service to warn home computer users about risks spreading over e-mail, the Web, file sharing and instant messaging networks. The Symantec Internet Threat Meter uses data from the company's Global Intelligence Network to rate Internet threats from low to high risk.

The new meter rates the risk of activities such as using e-mail or Web surfing based on the prevalence of high-risk threats and attacks using those mediums. For example, extremely high volumes of phishing and spam attacks or a critical e-mail client vulnerability would push the e-mail threat rating to "high risk," whereas a spike in adware and spyware would lift the risk rating for Web activities, Symantec said.

The meter is intended to alert consumers to the online threat environment and to attacks that may be stealthy and more targeted than in past years, Symantec said.

However, the new Internet Threat Meter provides little detail beyond a basic risk rating. On Feb. 28, for example, Symantec rated e-mail activity a "medium risk" and advised e-mail users to exercise "extra caution," despite "no high priority malicious code employing e-mail as a propagation vector." Web activities were deemed a "low risk," despite the observation that there are "multiple exploits available for recently patched vulnerabilities in various Microsoft client side software," and that "users could be affected by simply browsing to a Web site."