Microsoft warns of targeted exploits of unpatched flaw that could let attackers take control of victim's computer

Microsoft's PowerPoint application is being used in a new attack that exploits an unpatched vulnerability in the popular Office app. The software giant yesterday issued a security alert confirming "limited and targeted attacks" were under way using malicious PowerPoint files that exploit the flaw.

The exploits carry a Trojan, according to Microsoft, and in an interesting twist, the exploit files were recently submitted to the VirusTotal free malware-scanning site. "Either the miscreants who created these exploits were looking to see how antivirus products detect their new files, or the victims were looking to get some information about their maliciousness," blogged Cristian Craioveanu and Ziv Mador of Microsoft's Malware Protection Center.

When exploited, the vulnerability can give an attacker local rights to a user's machine if he opens the malicious PowerPoint file, which is currently being delivered via targeted email messages, but can also be pushed via a Website or instant messaging link.

The vulnerability affects PowerPoint 2000 Service Pack 3, PowerPoint 2002 Service Pack 3, PowerPoint 2003 Service Pack 3, and Microsoft Office 2004 for Mac . The newer Microsoft Office PowerPoint 2007 and Microsoft Office for Mac 2008 are immune.

"Microsoft will take the appropriate action to protect our customers, which may include providing a solution through our monthly security update release process, or an out-of-cycle security update, depending on customer needs," said Bill Sisk, security response communications manager for Microsoft, in a statement.

Paul Henry, security and forensic analyst for Lumension Security, blogged today that the attack is a reminder of the importance of least-privilege user rights. "...A reduced level of privilege for our users can afford significant risk mitigation in the current malware-ridden environment that exists. Simply put, you are not only limiting the users' rights, you are potentially limiting the rights of malware that may infect the users' PC," Henry said.

For now, Microsoft has provided a few workarounds for users to protect against the new PowerPoint attack:

  • Do not open or save Office files received unexpectedly from a trusted or untrusted source;

  • Use the Microsoft Office Isolated Conversion Environment to open those files; or

  • Use Microsoft Office File Block policy to ban Office 2003 and earlier files from being opened.

Graham Cluley, senior technology consultant for Sophos, says it's unclear whether Microsoft will have a fix ready in time for its April 14 patch update. "So take action now," he says in his new blog for Dark Reading. "Make sure your antivirus software is configured to automatically update as security vendors are rushing out detection routines, and ensure that your staff knows not to open unsolicited or unknown PowerPoint files, just in case they are carrying a dangerous payload."

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About the Author(s)

Kelly Jackson Higgins, Editor-in-Chief, Dark Reading

Kelly Jackson Higgins is the Editor-in-Chief of Dark Reading. She is an award-winning veteran technology and business journalist with more than two decades of experience in reporting and editing for various publications, including Network Computing, Secure Enterprise Magazine, Virginia Business magazine, and other major media properties. Jackson Higgins was recently selected as one of the Top 10 Cybersecurity Journalists in the US, and named as one of Folio's 2019 Top Women in Media. She began her career as a sports writer in the Washington, DC metropolitan area, and earned her BA at William & Mary. Follow her on Twitter @kjhiggins.

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