Microsoft Windows up to Server 2019 Application Compatibility Client Library access control

Summaryinfo

A vulnerability labeled as critical has been found in Microsoft Windows. This issue affects some unknown processing of the component Application Compatibility Client Library. The manipulation results in access control. This vulnerability is identified as CVE-2020-16876. The attack can be executed remotely. There is not any exploit available. It is best practice to apply a patch to resolve this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in Microsoft Windows (Operating System). Affected is an unknown part of the component Application Compatibility Client Library. 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. CVE summarizes:

<p>An elevation of privilege vulnerability exists when the Windows Application Compatibility Client Library improperly handles registry operations. An attacker who successfully exploited this vulnerability could gain elevated privileges.</p> <p>To exploit the vulnerability, an attacker would first need code execution on a victim system. An attacker could then run a specially crafted application.</p> <p>The security update addresses the vulnerability by ensuring the Windows Application Compatibility Client Library properly handles registry operations.</p>

The weakness was released 10/13/2020 as confirmed security guidance (Website). The advisory is available at portal.msrc.microsoft.com. This vulnerability is traded as CVE-2020-16876. The exploitability is told to be easy. It is possible to launch the attack remotely. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 02/24/2026). This vulnerability is assigned to T1068 by the MITRE ATT&CK project. The advisory points out:

An elevation of privilege vulnerability exists when the Windows Application Compatibility Client Library improperly handles registry operations. An attacker who successfully exploited this vulnerability could gain elevated privileges. To exploit the vulnerability, an attacker would first need code execution on a victim system. An attacker could then run a specially crafted application. The security update addresses the vulnerability by ensuring the Windows Application Compatibility Client Library properly handles registry operations.

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.

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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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