CVE-2021-36934 PoC — Windows Elevation of Privilege Vulnerability

Source

https://github.com/jmaddington/Serious-Sam---CVE-2021-36934-Mitigation-for-Datto-RMM

Associated Vulnerability

Title:Windows Elevation of Privilege Vulnerability (CVE-2021-36934)
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>.

Description

This PowerShell script will take the mitigation measures for CVE-2021-36934 described by Microsoft and the US CERT team.  https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934 https://kb.cert.org/vuls/id/506989  USE AT YOUR OWN RISK -- BACKUPS MAY BREAK.

Readme

# Overview #

This is a Datto RMM component to mitigate CVE-2021-36934, aka Serious SAM.

It follows the mitigation measures outlined at:
 * https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934
 * https://kb.cert.org/vuls/id/506989

USE AT YOUR OWN RISK. EXPECT THIS TO BREAK SOME BACKUPS TEMPORARILY.

Only basic error checking is in place.

# Usage #
Just upload the component into Datto RMM and run it. It will prompt you for a UDF to set that will either be set to
"Mitigated" or "UN-mitigated" allowing you to filter machines based on the mitigation. This is because current (reliable & easy)
tests for the vulnerability require UN-privileged access to run, not an easy task with Datto RMM.

If you use another RMM review the code comments, the script will still work but you may need to swap
out some vendor specific items.

# Improvements / Contributions #
Fork the repo and then submit a pull request.

File Snapshot

Remarks

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