Critical Flaw Affects Windows Server 2003

Microsoft alerted users on Wednesday to the first critical flaw found so far in Windows Server 2003. The flaw with the Remote Procedure Call protocol could allow a remote attacker to take full control of a Windows machine. It affects all supported versions of Windows except the consumer-oriented Windows Me.

While Windows Server 2003 was included in a bulletin involving a critical flaw last week, Microsoft rated the flaw of "moderate" severity for Windows Server 2003 because the more secure default installation of the server OS blocked off the vulnerable services. An early June bulletin also affected Windows Server 2003, but only through Internet Explorer 6.0, which also ships in Windows XP and is available for separate download. Again with that bulletin, Windows Server 2003 users had some protection against the vulnerability by the locked-down default installation.

The new bulletin is Microsoft's 26th of the year, and can be found here:

To underline the severity of the recent Microsoft bulletin, CERT issued its own alert to users through its e-mail notification service:

The critical RPC flaw is one of three security alerts Microsoft published on Wednesday. The other two were rated "important," the step below "critical" on Microsoft's internal threat scale. One affected Windows XP, the other involved Internet Security & Acceleration Server. The Windows XP bulletin is here. The ISA Server bulletin is here.

While Microsoft security bulletins had been fairly slow out of the gate in the first half of this year, their number has picked up in the last week. Microsoft has now issued six of this year's 28 Microsoft security bulletins since July 9.

About the Author

Scott Bekker is editor in chief of Redmond Channel Partner magazine.