Microsoft Unleashes Critical Update for Windows Server

Today is Patch Tuesday, and Microsoft is taking it easy on IT admins with a meager two security bulletins this month. But, don’t let the small number of updates lull you into a false sense of security. They may be few, but the patches this month are still crucial for network and computer security.

MS11-035 is rated as Critical and affects the WINS component of Windows Server 2003 and 2008, and MS11-036 is an Important security bulletins related to flaws in Microsoft PowerPoint.

WINS is a name resolution technology that is available–but not enabled by default–in Windows Server 2003 and Windows Server 2008. If it is not enabled, you have nothing to worry about, but IT admins who have enabled WINS should apply the update immediately because the vulnerability can be exploited remotely.

“What might make the WINS vulnerability appealing to attackers is that it is a server-side issue,” said Joshua Talbot, security intelligence manager, Symantec Security Response. “That means an attacker wouldn’t have to trick a user into doing anything. All they would have to do to exploit this is find a server running the vulnerable service and send that machine a malicious string of data.”

Andrew Storms, director of security operations for nCircle, says, “The most important patch this month will be the WINS bulletin. Microsoft is downplaying the bug, but there is potential here for remote code execution,” adding “WINS is a network aware application that does not require authentication, and many enterprises require WINS on their networks. Taken together, these factors mean that a lot of enterprises will find their internal network servers vulnerable to a remote code bug.”

Talbot also notes, however, that there is less risk on Windows Server 2008 than there is on Windows Server 2003 thanks to improved security on the more current OS. “Built-in protections such as DEP and ASLR in Server 2008 will probably keep most attackers from achieving a complete takeover. However, a complete system compromise appears to be more likely on Server 2003, which lacks the ASLR protection.”

That brings us to the debut of the updated exploitability index from Microsoft. A Microsoft spokesperson explains, “Microsoft is expanding its Exploitability Index to help customers on newer platforms better assess risk. The company will continue to offer an aggregate exploitability rating for each vulnerability across all previous product versions, but will also specifically break out Exploitability Index information for Microsoft’s latest products. This new system demonstrates the value of the security protections and mitigations available by default for new products.”

Storms points out that separating the current software from legacy software will be valuable information that will be hard to ignore, and should give IT admins the ammunition they need to build a strong business case for long overdue upgrades.