CVE-2021-36934

Known Exploited

Windows Elevation of Privilege Vulnerability

Description

An elevation of privilege vulnerability exists because of overly permissive Access Control Lists (ACLs) on multiple system files, including the Security Accounts Manager (SAM) database. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. An attacker must have the ability to execute code on a victim system to exploit this vulnerability. After installing this security update, you must manually delete all shadow copies of system files, including the SAM database, to fully mitigate this vulnerabilty. Simply installing this security update will not fully mitigate this vulnerability. See <a href="https://support.microsoft.com/topic/1ceaa637-aaa3-4b58-a48b-baf72a2fa9e7">KB5005357- Delete Volume Shadow Copies</a>.

7.8

CVSS

Severity: High

CVSS 3.1 •

CVSS 2.0 •

EPSS 90.30% Top 5%

KEV Since

Vendor Advisory microsoft.com

Affected: Microsoft Windows 10 Version 1809

Affected: Microsoft Windows 10 Version 1909

Affected: Microsoft Windows 10 Version 21H1

Affected: Microsoft Windows 10 Version 2004

Affected: Microsoft Windows 10 Version 20H2

References

Link	Tags
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934	patch vendor advisory
http://packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.html	third party advisory vdb entry
https://www.kb.cert.org/vuls/id/506989	third party advisory

Frequently Asked Questions

What is the severity of CVE-2021-36934?: CVE-2021-36934 has been scored as a high severity vulnerability.
How to fix CVE-2021-36934?: To fix CVE-2021-36934, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-36934 being actively exploited in the wild?: It is confirmed that CVE-2021-36934 is actively exploited. Be extra cautious if you are using vulnerable components. According to its EPSS score, there is a ~90% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-36934?: CVE-2021-36934 affects Microsoft Windows 10 Version 1809, Microsoft Windows 10 Version 1909, Microsoft Windows 10 Version 21H1, Microsoft Windows 10 Version 2004, Microsoft Windows 10 Version 20H2.