Microsoft today patched 19 vulnerabilities in Windows, IE9 (Internet Explorer 9), Excel and the .Net development framework, including four flaws in the just-released Windows 8 and its tablet spin-off Windows RT.

Of Tuesday’s six security updates, four were labeled “critical,” Microsoft’s most-severe threat ranking, while the remaining pair were pegged as “important” or “moderate.” Of the 19 vulnerabilities patched today, seven were tagged as critical.

“The IE9 is the one that should be patched first,” said Andrew Storms, director of security operations at nCircle Security, in an interview today. “It’s a drive-by,” he added, referring to the tactic that only requires hackers to trick users into browsing to a malicious website.

Doing that with an unpatched copy of IE9 could result in a successful hijacking of a Windows 7 or Vista PC. IE9 only runs on those two operating systems.

Source: InfoWorld