News

Microsoft Faced Big Issues in Fixing SMB Hole

Microsoft has come clean and confirmed that it took seven years to deliver its Server Message Block (SMB) fix.

• By Jabulani Leffall
• November 13, 2008

Redmond had a problem back then, according Security Response Center spokesperson Christopher Budd in a blog post. Basically, when the issue of an exploit affecting the application-level network protocol first came up in 2001, the software giant couldn't "make changes to address the issue without negatively impacting [other] network-based applications."

Providing a hotfix might have resulted in glitches that would have rendered "many, or nearly all, customers' network-based applications inoperable," Budd wrote.

The SMB vulnerability is related to a previously disclosed SMBRelay attack. Intruders equipped with a copy of the published exploit can get onto a workstation almost unnoticed and read and write files. They can also modify the Windows registry, delete objects and access e-mails, among other actions.

As a stop-gap over the past seven years, Microsoft recommended SMB signing, which is a security mechanism in the SMB protocol that can be used for authentication purposes. The signing function had been available before 2001 in Microsoft Windows NT 4.0 Service Pack 3 and Microsoft Windows 98.

With the SMB vulnerability fix in November's patch release, security experts who followed the issue are breathing a sigh of relief. Not only has a fix come out, but there now is a fuller explanation of the problem.

No one was more relieved than former Microsoft security staffer and current Chief Technology Officer at Shavlik Technologies, Eric Schultze. Having brought the problem to the attention of the software giant, Schultze had come to view the SMB exploit as a pebble in his shoe over the years.

"It's been a ride, as I had been pushing for a fix since 2001," he said. "We even ended up having a meeting with the OS and Internet Explorer teams. At first, we thought it was mitigated in IE, but that only worked for non-OS calls to SMB. Well, it looks like [Microsoft] has finally seen the light."

These days, vulnerabilities to Microsoft product and services rarely become public before Microsoft delivers a patch. And over the years, chances of widespread exploitation have become slimmer due to quicker response times from Microsoft.

Budd believes the Microsoft team got it right with the November patch.

"[The patch] addresses the SMBRelay issue but does so in a way that doesn't have the negative impact on applications that we originally believed addressing this issue would have," he wrote.