Microsoft Windows up to Server 2019 Group Policy privileges assignment

Summaryinfo

A vulnerability, which was classified as critical, has been found in Microsoft Windows. This affects an unknown function of the component Group Policy Handler. Performing a manipulation results in privileges assignment. This vulnerability is known as CVE-2020-16939. Attacking locally is a requirement. No exploit is available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability was found in Microsoft Windows (Operating System). It has been classified as critical. This affects an unknown functionality of the component Group Policy Handler. The manipulation with an unknown input leads to a privileges assignment vulnerability. CWE is classifying the issue as CWE-266. A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

<p>An elevation of privilege vulnerability exists when Group Policy improperly checks access. An attacker who successfully exploited this vulnerability could run processes in an elevated context.</p> <p>To exploit the vulnerability, an attacker would first have to log on to the system, and then run a specially crafted application to take control over the affected system.</p> <p>The security update addresses the vulnerability by correcting how Group Policy checks access.</p>

The weakness was published 10/13/2020 as confirmed security guidance (Website). It is possible to read the advisory at portal.msrc.microsoft.com. This vulnerability is uniquely identified as CVE-2020-16939. The exploitability is told to be easy. Attacking locally is a requirement. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 02/25/2026). The attack technique deployed by this issue is T1068 according to MITRE ATT&CK. The advisory points out:

An elevation of privilege vulnerability exists when Group Policy improperly checks access. An attacker who successfully exploited this vulnerability could run processes in an elevated context. To exploit the vulnerability, an attacker would first have to log on to the system, and then run a specially crafted application to take control over the affected system. The security update addresses the vulnerability by correcting how Group Policy checks access.

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.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Microsoft

Name

• Windows

Version

• 7 SP1
• 8.1
• 10
• 10 1607
• 10 1709
• 10 1803
• 10 1809
• 10 1903
• 10 1909
• 10 2004
• RT 8.1
• Server 1903
• Server 1909
• Server 2004
• Server 2008 R2 SP1
• Server 2008 SP2
• Server 2012
• Server 2012 R2
• Server 2016
• Server 2019

License

• commercial

Website

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

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion