CVE-2021-36934
Microsoft Windows SAM Local Privilege Escalation Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 24 February 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 67.25% probability · 99th percentile
- CISA KEV
- Listed 10 February 2022 · due 24 February 2022
- Affected
- microsoft/windows 10 1809 · microsoft/windows 10 1909 · microsoft/windows 10 2004 · microsoft/windows 10 20h2 · microsoft/windows 10 21h1
- Source
- secure@microsoft.com
CISA notes
Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-36934
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934Patch, Vendor Advisory
- http://packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.htmlThird Party Advisory, VDB Entry
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934Patch, Vendor Advisory
- https://www.kb.cert.org/vuls/id/506989Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36934US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.