MS preps five critical fixes for busy Patch Tuesday

ATL clean-up

Microsoft is lining up nine updates - five critical - for the August edition of its regular Patch Tuesday update cycle.

Eight of the nine patches plug vulnerabilities in Windows while the final update fixes a critical flaw in Microsoft Office (as well as Visual Studio, Microsoft ISA Server and Microsoft BizTalk Server).

Microsoft's pre-alert is light on details, as is the norm, but does explain that one of the critical Windows fixes will plug vulnerabilities in Outlook Express and Windows Media Player.

One of the critical flaws affects Microsoft's Client for Mac as well as Windows. All flavours of Windows - including servers and Vista - will need patching.

Last week Microsoft released an out-of-sequence patch that fixes a critical Internet Explorer flaw that was being actively exploited by hackers. At the same time Redmond also released a critical update for its Visual Studio development tools suite.

Both the two security problems stem from a fundamental flaw in Microsoft's ATL, or Active Template Library, which developers across the industry use to write application components (or more specifically Component Object Model code, including ActiveX controls). The flaw comes from a programming error involving an extra "&" character in a line of code. This, in turn, creates a buffer overflow risk for any applications that make use of the ATL code library.

Informed guesswork suggests that most of August's fixes will address flaws that can ultimately be traced back to the ATL snafu but were not as urgent as the MSVidCtl ActiveX control flaw that prompted an out of sequence IE patch last month.

The MSVidCtl ActiveX control flaw was been actively targeted by hackers and unpatched, the worst possible scenario. The only remaining zero-day vulnerabilities in this category is a flaw in Microsoft Office Web Components (OWC) which emerged a day after Microsoft's July Patch Tuesday update was published. Microsoft's pre-alert suggests that this flaw will be patched next week but this is by no means certain. ®

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