CVE-2021-36934
Confirmed PUBLISHEDWindows Elevation of Privilege Vulnerability
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
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.
- CVE Published
- Jul 22, 2021
- Exploitation Reported
- Feb 10, 2022
- CVSS
- 7.8 High
- EPSS
- —
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Microsoft |
Windows 10 Version 1809
|
10.0.0 to < 10.0.17763.2114 |
Affected |
| Microsoft |
Windows 10 Version 1909
|
10.0.0 to < 10.0.18363.1734 |
Affected |
| Microsoft |
Windows 10 Version 21H1
|
10.0.0 to < 10.0.19043.1165 |
Affected |
| Microsoft |
Windows 10 Version 2004
|
10.0.0 to < 10.0.19041.1165 |
Affected |
| Microsoft |
Windows 10 Version 20H2
|
10.0.0 to < 10.0.19042.1165 |
Affected |
CVE References
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934 portal.msrc.microsoft.com · CVE Record https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CV...
- packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.html packetstormsecurity.com · CVE Record http://packetstormsecurity.com/files/164006/HiveNightmare-AKA-Serious...
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2022-02-10 00:00 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:T/RC:C
Exploitation Status
Exploited in the wild
Recorded 2022-02-10 00:00:00 UTC · CISA
Proof of concept available
Recorded 2021-07-21 13:06:51 UTC · GitHub
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
github · Created 2021-08-02 13:47:17 UTC · 2 stars
POC experiments with Volume Shadow copy Service (VSS)
github · Created 2021-08-01 19:54:31 UTC · 2 stars
SeriousSAM Auto Exploiter
github · Created 2021-07-27 06:54:30 UTC · 7 stars
HiveNightmare aka SeriousSAM
github · Created 2021-07-26 08:01:08 UTC · 1 stars
github · Created 2021-07-24 14:58:10 UTC · 3 stars
C# PoC for CVE-2021-36934/HiveNightmare/SeriousSAM
github · Created 2021-07-22 14:53:09 UTC · 2 stars
Windows Elevation of Privilege Vulnerability (SeriousSAM)
github · Created 2021-07-22 12:24:24 UTC · 1 stars
CVE-2021-36934 PowerShell Fix
github · Created 2021-07-21 17:24:44 UTC · 5 stars
Detection and Mitigation script for CVE-2021-36934 (HiveNightmare aka. SeriousSam)
github · Created 2021-07-21 13:06:51 UTC · 10 stars
Fix for the CVE-2021-36934
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
00:00 UTC over 4 years ago00:00 UTC · over 4 years ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
07:05 UTC almost 5 years ago07:05 UTC · almost 5 years ago
CVE published
Vulnerability disclosed publicly
-
13:06 UTC about 5 years ago13:06 UTC · about 5 years ago
Public PoC available
Public proof-of-concept code published
-
00:00 UTC about 5 years ago00:00 UTC · about 5 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2021-36934
{
"cve_id": "CVE-2021-36934",
"title": "Windows Elevation of Privilege Vulnerability",
"affected_vendor": "Microsoft",
"affected_product": "Windows 10 Version 1809, Windows 10 Version 1909, Windows 10 Version 21H1, Windows 10 Version 2004, Windows 10 Version 20H2",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 7.8,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}