Multiple Microsoft Office versions impacted by an actively exploited zero-day

A zero-day flaw in Microsoft Office that could be exploited by attackers to achieve arbitrary code execution on Windows systems.

The cybersecurity researcher nao_sec discovered a malicious Word document (“05-2022-0438.doc”) that was uploaded to VirusTotal from Belarus. The document uses the remote template feature to fetch an HTML and then uses the “ms-msdt” scheme to execute PowerShell code.

The popular cybersecurity expert Kevin Beaumont published an analysis of the flaw.

“The document uses the Word remote template feature to retrieve a HTML file from a remote webserver, which in turn uses the ms-msdt MSProtocol URI scheme to load some code and execute some PowerShell.” reads the analysis published by Beaumont. “There’s a lot going on here, but the first problem is Microsoft Word is executing the code via msdt (a support tool) even if macros are disabled. Protected View does kick in, although if you change the document to RTF form, it runs without even opening the document (via the preview tab in Explorer) let alone Protected View.”

The issue affects multiple Microsoft Office versions, including Office, Office 2016, and Office 2021.

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Pierluigi Paganini

(SecurityAffairs – hacking, domain name system)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.