Actively exploited in the wild
Microsoft Windows SAM Local Privilege Escalation Vulnerability
Microsoft - Windows · Listed in the CISA KEV since 2022-02-10. This indicates confirmed attacks in production environments.
Required action: Apply updates per vendor instructions.
CVE-2021-36934
HighCVSS 7.8KEVExploitation Probability (EPSS)
Very high risk99th percentile - higher than 99% of all known CVEs
Summary
An elevation of privilege vulnerability exists due to overly permissive Access Control Lists (ACLs) on multiple system files, including the Security Accounts Manager (SAM) database. An attacker could run arbitrary code with SYSTEM privileges, install programs, view/change/delete data, or create new accounts with full user rights.
Risk Assessment
The risk is critical as an attacker could fully compromise the system with highest privileges. However, the attacker must be able to execute code on the victim system.
Recommendation
Install the security update and manually delete all shadow copies of system files, including the SAM database, as per KB5005357. Simply installing the update does not fully mitigate the vulnerability.
Original NVD description (English source)
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.