Microsoft issued eight updates on Tuesday - two more than expected - as part of its Patch Tuesday update cycle.
Redmond classifies six of the octet as critical, while independent security watchers reckon they all make the highest security grade. Worst of the bunch is an update for ActiveX controls that affects Visual Basic 6.0's runtime (MS08-070.
The buffer overflow risk affects Visual Studio, Foxpro, Frontpage and MS Project, along with third party apps that make use of the affected component. Worse still exploit code has been doing the rounds since April.
There's also a cumulative fix for Internet Explorer (MS08-073). But this fails to address an unpatched vulnerability that's already being used to mount drive-by download attacks, albeit on a limited basis. Other critical fixes cover flaws in Microsoft Office, Outlook, Windows Media Player and Windows Explorer.
Two bulletins - rated as important by Microsoft but critical by the SANS Institute's Internet Storm Centre (ISC) - tackle problems involving SharePoint Server and a separate bug involving Windows Media Player.
"The Microsoft elves have been busy and delivered everyone plenty of work to do this holiday season," said Andrew Storms, director of security at patching specialists nCircle. "All but one of the bulletins affect client-side applications and include all the usual suspects: IE, Office, ActiveX and GDI.
"Given the number of client side bugs with Microsoft products just patched, everyone should expect the attackers to celebrate the holiday season in their attack strategies."
Patching of systems will require systems updates, but needs to be carried out regardless of the potential inconvenience because of the heightened risk of phishing or malware attacks against unprotected systems, Andrew Clarke, senior vice president at security tools firm Lumension warned.
"Four critical updates (two involving Windows and two Microsoft Word and Excel) affecting four key pieces of software and major applications used within the enterprise, will require reboots to their systems and servers, adding a degree of complexity and disruption to network productivity," Clarke said.
"While it may be tempting to avoid restarting servers and systems especially during this busy time of year, it is imperative that all IT professionals pay particular attention to the critical updates and patch as quickly as business conditions permit." ®