CVEvulnerability
CVE-2021-36934
CISA Known Exploited Vulnerability
Microsoft Windows SAM Local Privilege Escalation Vulnerability — Microsoft Windows
If a Volume Shadow Copy (VSS) shadow copy of the system drive is available, users can read the SAM file which would allow any user to escalate privileges to SYSTEM level.
- Added to KEV
- 2022-02-10
- Remediation due
- 2022-02-24
- Ransomware use
- Unknown
- Required action
- Apply updates per vendor instructions.
- Notes
- https://nvd.nist.gov/vuln/detail/CVE-2021-36934
- Status
- Analyzed
- Published
- 2021-07-22
- Last modified
- 2026-08-10
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 7.8 HIGH — CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CVSS 3.1 ([email protected])
- 7.8 HIGH — CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CVSS 2.0 ([email protected])
- 4.6 MEDIUM — AV:L/AC:L/Au:N/C:P/I:P/A:P
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.
Affected configurations
• microsoft windows 10 1809 (< 10.0.17763.2114)
• microsoft windows 10 1909 (< 10.0.18363.1734)
• microsoft windows 10 2004 (< 10.0.19041.1165)
• microsoft windows 10 20h2 (< 10.0.19042.1165)
• microsoft windows 10 21h1 (< 10.0.19043.1165)
Related
Referenced by CWE · observed example (1)
- CWE-1220 Insufficient Granularity of Access Control weakness
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934 Patch, Vendor Advisory
- http://packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.html Third Party Advisory, VDB Entry
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934 Patch, Vendor Advisory
- https://www.kb.cert.org/vuls/id/506989 Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36934 US Government Resource