12 Apr. 2017

• By : UNIQ Solutions

Email attacks use unpatched vulnerability in Microsoft Word

Hackers are exploiting an unpatched vulnerability in Microsoft Word for the past few months to compromise computers and infect them with malware. The first report about the attacks came Friday from antivirus vendor McAfee after the company's researchers analyzed some suspicious Word files spotted a day earlier. It turned out that the files were exploiting a vulnerability it affects all Microsoft Office versions, including the latest Office 2016 running on Windows 10

The flaw is related to the Windows Object Linking and Embedding (OLE) feature in Microsoft Office that allows documents to embed references and links to other documents or objects, the McAfee researchers when the rogue documents used in this attack are opened, they reach out to an external server and download an HTA  file that contains malicious VBScript code. The HTA file is disguised as an RTF document and is automatically executed by searching back through its data, McAfee has tracked down attacks exploiting this vulnerability to late January.

Following McAfee's report, security researchers from FireEye also confirmed that they've been aware of these attacks and exploit for several weeks and have coordinated disclosure with Microsoft according to FireEye, the malicious Word documents are sent as email attachments. The company hasn't provided examples of the malicious emails, but because this is a previously undisclosed, zero-day vulnerability, the attacks are likely targeted toward a limited number of victims.

Microsoft is scheduled to release its monthly security updates on Tuesday, but it's not clear if a patch for this vulnerability will be included. The company did not immediately respond to a request for comment.

In the meantime, users should be wary of documents received from untrusted sources and should enable the Office Protected View mode because it can block this attack.