After having acknowledged the reported zero-day vulnerability in Windows 7, Microsoft has released a Security Advisory, which provides the requisite details about the scope and nature of a potential attack, and steps that the users can take immediately to ensure the protection of their vulnerable systems.

The vulnerability in question essentially affects the Server Message Block (SMB) protocol that is used for file and printer sharing, and can reportedly be exploited by attackers to remotely crash any computer running Windows 7 or Windows Server 2008 R2. Microsoft has already acknowledged that a functional exploit code has been published for the reported flaw.

In the recently-issued advisory, Microsoft has clarified that the reported vulnerability is fairly limited in its potential impact - it can neither be used by the attacker for taking control of affected systems nor for installing malicious software.

Saying that it is working on a security update to fix the bug, Microsoft said that, till the time the December security patch is released, users can protect vulnerable systems from any potential threat by blocking the SMB-protocol-specific TCP ports 139 and 445 at the firewall.

Microsoft has further elaborated that though the recommended measure will help prevent any exploits from outside of the network, it will also disable the ability to use certain functions and services through the firewall, including Group Policy, Net Logon, and Computer Browser.