Microsoft released eight patches, five critical, on Tuesday as part of its regular Patch Tuesday update cycle.

The bulletins collectively cover 23 separate vulnerabilities, six of which have been targeted by exploit code. The updates cover a fix (MS09-009) for a flaw in Excel that's become the target of attacks of recent weeks.

Missing from the list is relief for a zero-day vulnerability in PowerPoint, actively targeted by hackers since last month.

Microsoft's summary can be found here. A more colourful and easy to understand overview from the Internet Storm Centre can be found here.

Virtual all Windows systems - client and server - will need patching. According to patching security firm Lumension, six of the eight bulletins require a restart, including one critical flaw (covered by MS09-013) that requires the restart of Windows 2003 and 2008 Servers. ®

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