Microsoft looking into new SMB vulnerability report

A researcher this week published proof-of-concept code that allows an attacker to exploit a vulnerability in Windows 7 and Server 2008 Release 2 to crash systems.

The flaw, detailed by Laurent Gaffie in a blog post on Wednesday, lies in the Windows Server Message Block (SMB) and requires no user interaction to exploit.

Attackers can remotely crash systems if a victim machine receives malformed packets, Jonathan Leopando, a member of the Trend Micro technical communications team, said in a blog post Thursday.

"What ever your firewall is set to, you can get remotely smashed via IE (Internet Explorer) or even via some NBNS (NetBios Name Service) tricks," Gaffie said.

Christopher Budd, security response communications lead at Microsoft, told SCMagazineUS.com in a statement Friday that the software giant is aware of the purported vulnerability, which is said to cause a denial-of-service attack.

"We're currently unaware of any attacks trying to use the claimed vulnerability or of customer impact," Budd said. "Once we're done investigating, we will take appropriate action to help protect customers."

Users are encouraged to block ports used by the SMB protocol until Microsoft offers workarounds or permanent fix,  Leopando said.

In October, Microsoft patched another serious vulnerability in the SMB protocol that Gaffie discovered.