Microsoft Windows up to Server 2019 Hard Link privileges management

Summaryinfo

A vulnerability was found in Microsoft Windows. It has been classified as critical. The affected element is an unknown function of the component Hard Link Handler. This manipulation causes privileges management. This vulnerability is registered as CVE-2020-0840. Remote exploitation of the attack is possible. No exploit is available. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability was found in Microsoft Windows (Operating System). It has been declared as critical. Affected by this vulnerability is an unknown code block of the component Hard Link Handler. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

An elevation of privilege vulnerability exists when Windows improperly handles hard links, aka 'Windows Hard Link Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0841, CVE-2020-0849, CVE-2020-0896.

The weakness was published 03/10/2020 as confirmed security update guide (Website). It is possible to read the advisory at portal.msrc.microsoft.com. The public release has been coordinated with Microsoft. This vulnerability is known as CVE-2020-0840. The attack can be launched remotely. The requirement for exploitation is a single authentication. 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 03/11/2020). 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 Windows improperly handles hard links. An attacker who successfully exploited this vulnerability could overwrite a targeted file leading to an elevated status.

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

Similar entries are available at VDB-151139, VDB-151138, VDB-151137 and VDB-151136. Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Microsoft

Name

• Windows

Version

• 8.1
• 10
• 10 1607
• 10 1709
• 10 1803
• 10 1809
• 10 1903
• 10 1909
• RT 8.1
• Server 1803
• Server 1903
• Server 1909
• 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

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