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

Source

https://github.com/n3tsurge/CVE-2021-36934

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 KB5005357- Delete Volume Shadow Copies.

Description

Detection and Mitigation script for CVE-2021-36934 (HiveNightmare aka. SeriousSam)

Readme

��# CVE-2021-36934



## Usage



### Detection



```

.\Get-HiveNightmareStatus.ps1

```



### Detection for management tools that need True/False output

```

.\Get-HiveNightmareStatus.ps1 -PostureCheck

```



### Remediation

```

# For initial SAM fixes and vss removal

.\Get-HiveNightmareStatus.ps1 -Remediate



# Remediate even if the checks say healthy or are partial

.\Get-HiveNightmareStatus.ps1 -Remediate -Force

```



### Exploitability Test

```

.\Get-HiveNightmareStatus.ps1 -Exploit

```



## SentinelOne customers



1. Apply the policy override in `sentinelone-policy-override.txt`

2. Make sure the policy is applied using `(.\sentinelctl.exe config | Select-String -Pattern "vssSnapshots|penetration")`



```powershell

$ (.\sentinelctl.exe config | Select-String -Pattern "vssSnapshots|penetration")



agent.enginesWantedState.penetration                                            off

agent.vssSnapshots                                                              false

```

File Snapshot

Remarks

1. It is advised to access via the original source first.

2. Local POC snapshots are reserved for subscribers — if the original source is unavailable, the local mirror is part of the paid plan.

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