Microsoft has taken the unusual step of releasing a patch for a Windows security vulnerability outside of its normal monthly update cycle.
The second Tuesday of every month, known as Patch Tuesday, is normally when Microsoft releases security and performance updates, though this particular patch was considered important enough to be released immediately.
"A security issue has been identified that could allow an unauthenticated remote attacker to compromise your Microsoft Windows-based system and gain control over it," a statement on the Windows Update website reads.
The fix, known as MS08-067, is rated as 'critical' if you are using Windows XP and 'important' if you use Windows Vista.
Microsoft is encouraging Windows users to install the update as soon as possible.
"Because the vulnerability is potentially wormable on those older versions of Windows, we're encouraging customers to test and deploy the update as soon as possible," said Christopher Budd of Microsoft.
Security experts speculated as to why Microsoft had chosen to release the patch when it did.
"Hackers may have already been actively exploiting this bug days before Microsoft received wind of the vulnerability. But kudos to Microsoft for delivering this immediate solution to prevent more users from becoming victims," said Carolyn Guevarra of Trend Micro.
http://update.microsoft.com www.trendmicro.com