Microsoft released six patches on Tuesday night - three critical - as part of its regular Patch Tuesday update cycle.
After the biggest ever patch cycle in October, November's patch train arrives with a far lighter load. The three critical fixes focus on bugs in various supported versions of Windows, though not Windows 7. Users of the latest version of Microsoft's operating system get a pass this month and don't need to fix OS-system related flaws, though they may have some work on in fixing application-related bugs.
One of the three critical fixes (MS09-065) addresses several vulnerabilities in the Windows kernel and replaces the previously released bulletin MS09-025. All supported versions of Windows bar Windows 7 are affected.
Another critical update (MS09-63) tackles a vulnerability in the Web Services on Devices Application Programming Interface (WSDAPI) in both Vista and Windows 2003. The last of the three critical updates (MS09-064) resolves a vulnerability in Microsoft Windows 2000 License Logging Server.
"MS09-065, a bug in the Windows kernel, is this month's most serious issue," said Andrew Storms, director of security operations at network security firm nCircle. "The vulnerability allows for remote code execution, and the attack code can be embedded inside MS Office files or be hosted on websites. Simply browsing an infected website will compromise unsuspecting users."
Two of Redmond's lesser risk (by its definition, at least) "important" updates cover security bugs in Word and Office, respectively. Both Windows PC and Mac implementations of Microsoft Office need updating. Each update replaces a bulletin previously released earlier this year.
The last of three important updates (MS09-066) grapples with a vulnerability in Active Directory and replaces the previously released bulletin MS09-018.