Microsoft Windows up to Server 2019 Unified Extensible Firmware Interface access control

Summaryinfo

A vulnerability identified as critical has been detected in Microsoft Windows. This impacts an unknown function of the component Unified Extensible Firmware Interface. Performing a manipulation results in access control. This vulnerability was named CVE-2020-16910. The attack may be initiated remotely. There is no available exploit. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in Microsoft Windows (Operating System). This affects some unknown functionality of the component Unified Extensible Firmware Interface. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

<p>A security feature bypass vulnerability exists when Microsoft Windows fails to handle file creation permissions, which could allow an attacker to create files in a protected Unified Extensible Firmware Interface (UEFI) location.</p> <p>To exploit this vulnerability, an attacker could run a specially crafted application to bypass Unified Extensible Firmware Interface (UEFI) variable security in Windows.</p> <p>The security update addresses the vulnerability by correcting security feature behavior to enforce permissions.</p>

The weakness was presented 10/13/2020 as confirmed security guidance (Website). The advisory is shared at portal.msrc.microsoft.com. This vulnerability is uniquely identified as CVE-2020-16910. The exploitability is told to be easy. It is possible to initiate the attack remotely. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 02/24/2026). MITRE ATT&CK project uses the attack technique T1068 for this issue. The advisory points out:

A security feature bypass vulnerability exists when Microsoft Windows fails to handle file creation permissions, which could allow an attacker to create files in a protected Unified Extensible Firmware Interface (UEFI) location. To exploit this vulnerability, an attacker could run a specially crafted application to bypass Unified Extensible Firmware Interface (UEFI) variable security in Windows. The security update addresses the vulnerability by correcting security feature behavior to enforce permissions.

It is declared as proof-of-concept.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Microsoft

Name

• Windows

Version

• 10
• 10 1607
• 10 1709
• 10 1803
• 10 1809
• 10 1903
• 10 1909
• 10 2004
• Server 1903
• Server 1909
• Server 2004
• Server 2016
• Server 2019

License

• commercial

Website

• Vendor: https://www.microsoft.com/
• Product: https://www.microsoft.com/en-us/windows

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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