Microsoft working to fix Office document vulnerability on Windows 10
The Cybersecurity and Infrastructure Security Agency encourages people and organizations to review a recent security advisory from Microsoft.
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What you need to know
Microsoft is looking into a report of a remote code execution vulnerability in MSHTML that affects Windows. The company explains in asecurity reportthat it is aware of targeted attacks that attempt to exploit the vulnerability by using Microsoft Office documents. Both Microsoft Defender Antivirus and Microsoft Defender for Endpoint provide detection and protection for the vulnerability.
Microsoft explains that an attacker could use malicious ActiveX control that’s hidden within an Office document. Threat actors craft these documents in a way that could trick people into enabling the ActiveX control. Microsoft does not specifically mention the recent"Windows 11 Alpha" malware attacks, but the methods used in that attack appear similar to what Microsoft describes in its report.
The attacks mentioned by Microsoft also appear to be connected to theupcoming change in how Office handles Trusted Documents. The Microsoft 365 roadmap outlines that Office 365 will soon follow IT administrator policies that block Active Content in Trusted Documents.
Microsoft outlines mitigations and workarounds for the issue that admins can utilize now. The company explains that “by default, Microsoft Office opens documents from the internet in Protected View or Application Guard for Office both of which prevent the current attack.”
People can also disable the installation of ActiveX controls in Internet Explorer to mitigate the attack. It’s important to note that editing the registry comes with risks if done incorrectly.
The Cybersecurity and Infrastructure Security Agency encourages people to look through Microsoft’s mitigations and workarounds.
.@CISAgovencourages users and organizations to review Microsoft’s mitigations and workarounds to address CVE-2021-40444, a remote code execution vulnerability in Microsoft Windows:https://t.co/PY3WTgvzRahttps://t.co/zUvbfTjRTd.@CISAgovencourages users and organizations to review Microsoft’s mitigations and workarounds to address CVE-2021-40444, a remote code execution vulnerability in Microsoft Windows:https://t.co/PY3WTgvzRahttps://t.co/zUvbfTjRTd— US-CERT (@USCERT_gov)September 7, 2021September 7, 2021
After Microsoft completes its investigation, it may roll out updates for the issue through normal Patch Tuesday updates or out-of-cycle security updates.
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Sean Endicott is a tech journalist at Windows Central, specializing in Windows, Microsoft software, AI, and PCs. He’s covered major launches, from Windows 10 and 11 to the rise of AI tools like ChatGPT. Sean’s journey began with the Lumia 740, leading to strong ties with app developers. Outside writing, he coaches American football, utilizing Microsoft services to manage his team. He studied broadcast journalism at Nottingham Trent University and is active on X @SeanEndicott_ and Threads @sean_endicott_.
