Microsoft is warning users about targeted attacks against a new vulnerability in several versions of Windows and Office that could allow an attacker to take over a user’s machine. The bug, which is not yet patched, is being used as part of targeted attacks with malicious email attachments, mainly in the Middle East and Asia.
In the absence of a patch, Microsoft has released a FixIt tool for the vulnerability, which prevents exploits against the vulnerability from working. The bug affects Windows Vista, Windows Server 2008 and Microsoft Office 2003 through 2010.
“The exploit requires user interaction as the attack is disguised as an email requesting potential targets to open a specially crafted Word attachment. If the attachment is opened or previewed, it attempts to exploit the vulnerability using a malformed graphics image embedded in the document. An attacker who successfully exploited the vulnerability could gain the same user rights as the logged on user,” the Microsoft advisory says.
The vulnerability doesn’t affect the current versions of Windows, the company said, and users who are running potentially vulnerable products can take a couple of actions in order to protect themselves. Installing the FixIt tool will help prevent exploitation, as will deploying the Enhanced Mitigation Experience Toolkit (EMET), which helps mitigate exploits against certain classes of bugs.
“The vulnerability is a remote code execution vulnerability that exists in the way affected components handle specially crafted TIFF images. An attacker could exploit this vulnerability by convincing a user to preview or open a specially crafted email message, open a specially crafted file, or browse specially crafted web content. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights<’ Microsoft officials said.