February 10, 2022 · Applied Cybernetics Group
CVE-2021-36934 — Microsoft Windows
Microsoft Windows SAM Local Privilege Escalation Vulnerability
- Added to KEV
2022-02-10- Federal due date
2022-02-24- Vendor
- Microsoft
- Product
- Windows
- EPSS
- 99.3th percentile (score 0.673, as of
2026-09-16) - NVD CVSS v3.1
- 7.8 (HIGH)
- Ransomware use
- Unknown
- ATT&CK
- T1068 , T1078 · signal rollup
- Upstream
- https://nvd.nist.gov/vuln/detail/CVE-2021-36934
CISA short description
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.
Required action
Apply updates per vendor instructions.
NVD 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.