CVE-2021-36934

Microsoft Windows: SAM Local Privilege Escalation

As of , CVE-2021-36934 in Microsoft Windows is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 10 February 2022
US federal deadline
24 February 202214 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.67Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
0.08 on 10 February 2022EPSS on the day CISA listed it.
Public exploit
1 Metasploit module
Fix
No vendor link in CISA's entry

What CISA says to do

Apply updates per vendor instructions.

CISA's required action

What the flaw is

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.

CISA's 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.

The CVE record's description, from microsoft

CVE published
22 July 2021
Assigned by
microsoft
CVSS
7.8 High (CVSS 3.1, from the CNA)
CWE-1220
Insufficient Granularity of Access Control
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

Public exploits

Facts from Metasploit's module list and Exploit-DB's index; we never copy exploit code.

  • Metasploit: Windows SAM secrets leak - HiveNightmarepost module, rank normal

Windows: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2025-60710Link FollowingMicrosoft WindowsPatch nowRansomware use, listed within a year0.05
CVE-2008-4250Buffer OverflowMicrosoft WindowsPatch this weekMetasploit module; EPSS 0.99; verified Exploit-DB entry0.99
CVE-2008-0015Video ActiveX Control Remote Code ExecutionMicrosoft WindowsPatch this weekMetasploit module; EPSS 0.77; verified Exploit-DB entry0.77
CVE-2013-3918Out-of-Bounds WriteMicrosoft WindowsPatch this weekMetasploit module; EPSS 0.74; verified Exploit-DB entry0.74
CVE-2010-2568Remote Code ExecutionMicrosoft WindowsPatch this weekMetasploit module; EPSS 0.91; verified Exploit-DB entry0.91
CVE-2015-0016TS WebProxy Directory TraversalMicrosoft WindowsPatch this weekMetasploit module; EPSS 0.76; verified Exploit-DB entry0.76
CVE-2015-2426Adobe Type Manager Library Remote Code ExecutionMicrosoft WindowsPatch this weekMetasploit module; EPSS 0.87; verified Exploit-DB entry0.87
CVE-2014-6332Object Linking & Embedding (OLE) Automation Array Remote Code ExecutionMicrosoft WindowsPatch this weekMetasploit module; EPSS 0.95; verified Exploit-DB entry0.95
CVE-2017-0146SMB Remote Code ExecutionMicrosoft WindowsPatch this weekRansomware use; Metasploit module; EPSS 0.90; verified Exploit-DB entry0.90
CVE-2014-4114Object Linking & Embedding (OLE) Remote Code ExecutionMicrosoft WindowsPatch this weekMetasploit module; EPSS 0.82; verified Exploit-DB entry0.82

All 174 entries for Windows

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