CriticalCVE-2022-37969

Windows Common Log File System Driver Elevation of Privilege Vulnerability (CVE-2022-37969)

Published 13.09.2022Last modified 10.09.2026In CISA KEV since 14.09.2022Sources: CVE.org, SingCERT

What is affected, what to do

Windows Common Log File System Driver Elevation of Privilege Vulnerability

The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. Update Microsoft Windows 10 Version 1809 to version 10.0.17763.3406, Microsoft Windows Server 2019 to version 10.0.17763.3406, Microsoft Windows Server 2019 (Server Core installation) to version 10.0.17763.3406. Immediate actions, mitigation and detection rules are in the runbook below.

Affected: Microsoft Windows 10 Version 1809 lt 10.0.17763.0..10.0.17763.3406
Microsoft Windows Server 2019 lt 10.0.17763.0..10.0.17763.3406
Microsoft Windows Server 2019 (Server Core installation) lt 10.0.17763.0..10.0.17763.3406
Microsoft Windows 10 Version 21H1 lt 10.0.0..10.0.19043.2006
Microsoft Windows Server 2022 lt 10.0.20348.0..10.0.20348.1006
Microsoft Windows 10 Version 20H2 lt 10.0.0..10.0.19042.2006
Microsoft Windows 11 version 21H2 lt 10.0.0..10.0.22000.978
Microsoft Windows 10 Version 21H2 lt 10.0.19043.0..10.0.19044.2006
Microsoft Windows 10 Version 1507 lt 10.0.10240.0..10.0.10240.19444
Microsoft Windows 10 Version 1607 lt 10.0.14393.0..10.0.14393.5356
Microsoft Windows Server 2016 lt 10.0.14393.0..10.0.14393.5356
Microsoft Windows Server 2016 (Server Core installation) lt 10.0.14393.0..10.0.14393.5356
Microsoft Windows 7 lt 6.1.0..6.1.7601.26115
Microsoft Windows 7 Service Pack 1 lt 6.1.0..6.1.7601.26115
Microsoft Windows 8.1 lt 6.3.0..6.3.9600.20571
Microsoft Windows Server 2008 Service Pack 2 lt 6.0.6003.0..6.0.6003.21666
Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) lt 6.0.6003.0..6.0.6003.21666
Microsoft Windows Server 2008 R2 Service Pack 1 lt 6.1.7601.0..6.1.7601.26115
Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) lt 6.1.7601.0..6.1.7601.26115
Microsoft Windows Server 2012 lt 6.2.9200.0..6.2.9200.23865
Microsoft Windows Server 2012 (Server Core installation) lt 6.2.9200.0..6.2.9200.23865
Microsoft Windows Server 2012 R2 lt 6.3.9600.0..6.3.9600.20571
Microsoft Windows Server 2012 R2 (Server Core installation) lt 6.3.9600.0..6.3.9600.20571
Fixed in: Microsoft Windows 10 Version 1809 10.0.17763.3406
Microsoft Windows Server 2019 10.0.17763.3406
Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.3406
Microsoft Windows 10 Version 21H1 10.0.19043.2006
Microsoft Windows Server 2022 10.0.20348.1006
Microsoft Windows 10 Version 20H2 10.0.19042.2006
Microsoft Windows 11 version 21H2 10.0.22000.978
Microsoft Windows 10 Version 21H2 10.0.19044.2006
Microsoft Windows 10 Version 1507 10.0.10240.19444
Microsoft Windows 10 Version 1607 10.0.14393.5356
Microsoft Windows Server 2016 10.0.14393.5356
Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.5356
Microsoft Windows 7 6.1.7601.26115
Microsoft Windows 7 Service Pack 1 6.1.7601.26115
Microsoft Windows 8.1 6.3.9600.20571
Microsoft Windows Server 2008 Service Pack 2 6.0.6003.21666
Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) 6.0.6003.21666
Microsoft Windows Server 2008 R2 Service Pack 1 6.1.7601.26115
Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.26115
Microsoft Windows Server 2012 6.2.9200.23865
Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.23865
Microsoft Windows Server 2012 R2 6.3.9600.20571
Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.20571

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Metrics

7.8

Priority

XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

Source: NVD, CVSS v3

7.8

CVSS v3

Severity High on the scale from 0 to 10.

Source: CVE.org, SingCERT

28.3 %

EPSS score

Elevated — model estimates 10-50% exploitation likelihood.

Source: FIRST EPSS, percentile 98.1

Show all metrics

Severity: Critical
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 242.41 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: actively exploitedSource: CSA/SingCERT How we classify
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 7.8 Methodology
CVSS v3 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 7.8
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 28.3 %; Elevated — model estimates 10-50% exploitation likelihood.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 98.1; Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: Actively exploited
Published: 13.09.2022
In CISA KEV since The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: 14.09.2022

Response and mitigation

Why act now?

Prioritisation rationale

CVE-2022-37969 is a local privilege escalation that takes a low-privileged user to full SYSTEM without any user interaction. Attackers use it as the second stage after phishing, stolen credentials or another initial code-execution foothold. CISA's ransomware flag and the very high exploitation likelihood show it is a staple of intrusion chains that end in EDR tampering, credential theft and encryption. Because virtually every Windows client is affected, score your exposure by the number of user endpoints and multi-user hosts, not by internet reachability. For NIS2/KRITIS organisations, handle it as a high priority with a shortened patch SLA, and escalate any unpatchable legacy hosts as critical.

01
Runbook step 1
Immediate response (0-24 h)
- Deploy the Microsoft September 2022 security update containing the CLFS fix to all Windows clients, or confirm it is already installed. Reference builds from the context: Windows 10 1507 10.0.10240.19444, 1607 10.0.14393.5356, 1809 10.0.17763.3406, 20H2 10.0.19042.2006, 21H1 10.0.19043.2006, 21H2 10.0.19044.2006, Windows 11 21H2 10.0.22000.978. Treat anything below these builds as vulnerable. Look up the exact KB ID in the MSRC advisory for CVE-2022-37969.
- Run a build inventory via Intune, SCCM or EDR (e.g. KQL DeviceInfo | summarize arg_max(Timestamp,*) by DeviceId | project DeviceName, OSPlatform, OSBuild) and escalate outliers.
- Check the MSRC advisory to see whether Windows Server builds sharing the same codebase (the 1607/1809 kernels) are affected, and add them to the same patch wave.
- Treat Windows 7 hosts without ESU coverage as unpatchable. Disconnect them, or move them into an isolated segment with no user logons.
- Patch multi-user systems first: terminal servers, RDS, Citrix and VDI hosts, and jump hosts. On these, one compromised standard account is enough to take over SYSTEM.
- If exploitation is suspected, isolate the host. Then rotate local admin credentials (LAPS) and any domain credentials cached on it, since an LSASS dump should be assumed after a SYSTEM escalation.
02
Runbook step 2
Mitigation layers
- Configuration: Microsoft lists no workaround. clfs.sys is a core OS driver and must not be disabled. Patching is the only complete fix.
- Application control: Enforce WDAC or AppLocker and block execution from user-writable paths (%TEMP%, %APPDATA%, C:\Users\Public, Downloads). This stops a dropped exploit binary from ever running.
- Endpoint hardening: Enable ASR rules, especially "Block executable files unless they meet prevalence, age or trusted list criterion" and "Block credential stealing from LSASS". Add LSA protection (RunAsPPL) and Credential Guard to blunt what attackers do after escalating.
- IAM/least privilege: Restrict interactive logon on servers to admin-tier accounts. Remove interactive logon rights from service accounts and disable unused local accounts.
- Shrink initial access: The bug requires local code execution. Enforce macro blocking, mail attachment filtering and restrictions on ISO, LNK and script files as upstream barriers.
- Network segmentation: Move unpatched legacy hosts into dedicated VLANs with no SMB, RDP or WinRM reachability to domain controllers or admin workstations. This limits lateral movement after a successful escalation.
03
Runbook step 3
Detection rules
- Sysmon EID 11 (FileCreate): Non-system processes creating *.blf or CLFS container files in user-writable paths. Sigma shape: TargetFilename|endswith: '.blf' AND Image|contains: ['\Users\', '\Temp\', '\ProgramData\'].
- Integrity jump in process lineage (Sysmon EID 1 / Security 4688): A child process running as NT AUTHORITY\SYSTEM with System integrity, whose parent runs at Medium integrity under a standard user and is not services.exe, svchost.exe or wininit.exe. Typical pattern: unsigned binary → cmd.exe or powershell.exe as SYSTEM.
- EDR telemetry: Alerts for token manipulation or token swapping, or for kernel memory tampering. KQL starter: DeviceProcessEvents | where AccountSid == "S-1-5-18" and InitiatingProcessAccountSid !startswith "S-1-5-18" and InitiatingProcessAccountSid !startswith "S-1-5-19" and InitiatingProcessAccountSid !startswith "S-1-5-20".
- Post-exploitation follow-on: Shortly after the integrity jump, watch for LSASS access (Sysmon EID 10, TargetImage ending in lsass.exe, GrantedAccess 0x1010/0x1410), new service installs (System 7045) or Defender being disabled (Event 5001). Correlate these with the originating user context.
- Stability signals: Clusters of BSODs (System Event 1001 BugCheck, Event 41 Kernel-Power) referencing clfs.sys can indicate failed exploit attempts.

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

Windows Common Log File System Driver Elevation of Privilege Vulnerability

Source: cvelistv5, NVD (NIST), CISA KEV Catalog, CVE.org (MITRE), CSA/SingCERT

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
Microsoft	Windows 10 Version 1507	`10.0.10240.0 – < 10.0.10240.19444`	`10.0.10240.19444`
Microsoft	Windows 10 Version 1607	`10.0.14393.0 – < 10.0.14393.5356`	`10.0.14393.5356`
Microsoft	Windows 10 Version 1809	`10.0.17763.0 – < 10.0.17763.3406`	`10.0.17763.3406`
Microsoft	Windows 10 Version 20H2	`10.0.0 – < 10.0.19042.2006`	`10.0.19042.2006`
Microsoft	Windows 10 Version 21H1	`10.0.0 – < 10.0.19043.2006`	`10.0.19043.2006`
Microsoft	Windows 10 Version 21H2	`10.0.19043.0 – < 10.0.19044.2006`	`10.0.19044.2006`
Microsoft	Windows 11 version 21H2	`10.0.0 – < 10.0.22000.978`	`10.0.22000.978`
Microsoft	Windows 7	`6.1.0 – < 6.1.7601.26115`	`6.1.7601.26115`
Microsoft	Windows 7 Service Pack 1	`6.1.0 – < 6.1.7601.26115`	`6.1.7601.26115`
Microsoft	Windows 8.1	`6.3.0 – < 6.3.9600.20571`	`6.3.9600.20571`
Microsoft	Windows Server 2008 R2 Service Pack 1	`6.1.7601.0 – < 6.1.7601.26115`	`6.1.7601.26115`
Microsoft	Windows Server 2008 R2 Service Pack 1 (Server Core installation)	`6.1.7601.0 – < 6.1.7601.26115`	`6.1.7601.26115`
Microsoft	Windows Server 2008 Service Pack 2	`6.0.6003.0 – < 6.0.6003.21666`	`6.0.6003.21666`
Microsoft	Windows Server 2008 Service Pack 2 (Server Core installation)	`6.0.6003.0 – < 6.0.6003.21666`	`6.0.6003.21666`
Microsoft	Windows Server 2012	`6.2.9200.0 – < 6.2.9200.23865`	`6.2.9200.23865`
Microsoft	Windows Server 2012 (Server Core installation)	`6.2.9200.0 – < 6.2.9200.23865`	`6.2.9200.23865`
Microsoft	Windows Server 2012 R2	`6.3.9600.0 – < 6.3.9600.20571`	`6.3.9600.20571`
Microsoft	Windows Server 2012 R2 (Server Core installation)	`6.3.9600.0 – < 6.3.9600.20571`	`6.3.9600.20571`
Microsoft	Windows Server 2016	`10.0.14393.0 – < 10.0.14393.5356`	`10.0.14393.5356`
Microsoft	Windows Server 2016 (Server Core installation)	`10.0.14393.0 – < 10.0.14393.5356`	`10.0.14393.5356`
Microsoft	Windows Server 2019	`10.0.17763.0 – < 10.0.17763.3406`	`10.0.17763.3406`
Microsoft	Windows Server 2019 (Server Core installation)	`10.0.17763.0 – < 10.0.17763.3406`	`10.0.17763.3406`
Microsoft	Windows Server 2022	`10.0.20348.0 – < 10.0.20348.1006`	`10.0.20348.1006`

Vendors and products

Affected operating systems

Affected operating systems

Windows	microsoft	windows_10_1507	—
Windows	microsoft	windows_10_1607	—
Windows	microsoft	windows_10_1809	—
Windows	microsoft	windows_10_20h2	—
Windows	microsoft	windows_10_21h1	—
Windows	microsoft	windows_10_21h2	—
Windows	microsoft	windows_11_21h2	—
Windows	microsoft	windows_7	—
Windows	microsoft	windows_8.1	—
Windows	microsoft	windows_rt_8.1	—
Windows	microsoft	windows_server_2008	`r2`
Windows	microsoft	windows_server_2008	—
Windows	microsoft	windows_server_2012	`r2`
Windows	microsoft	windows_server_2012	—
Windows	microsoft	windows_server_2016	—
Windows	microsoft	windows_server_2019	—
Windows	microsoft	windows_server_2022	—

Public exploit references

Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

Public exploit references

CISA KEV Catalog	CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov	actively exploited	14.09.2022
CSA/SingCERT	September 2022 Monthly Patch (opens in a new tab)CSA/SingCERT	actively exploited	13.09.2022

References & sources

Microsoft Security Update GuideWindows Common Log File System Driver Elevation of Privilege VulnerabilityVendor advisory
cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2022-37969government-resource

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

10.09.2026Record modifiedMicrosoft

New references:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-37969

Show 3 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-37969
Reference	removed	https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-37969	—
Reference type	removed	https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-37969 Types: Patch, Vendor Advisory	—

Source identifier: secure@microsoft.com

10.09.2026Record modifiedCISA ADP

CISA assessment (SSVC): exploitation: active, automatable: no

New references:

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-37969

Show 4 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-37969
Reference	removed	https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-37969	—
Reference type	removed	https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-37969 Types: US Government Resource	—
SSVC assessment	changed	{"id":"CVE-2022-37969","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2025-01-27T22:27:58.996469Z"}	{"id":"CVE-2022-37969","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2022-09-14T00:00:00+00:00"}

Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

10.09.2026Record modifiedCVE Program

New references:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-37969

Show 3 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-37969
Reference	removed	https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-37969	—
Reference type	removed	https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-37969 Types: Patch, Vendor Advisory	—

Source identifier: af854a3a-2127-422b-91ae-364da2661108

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<a href="https://intel.neosec.eu/en/cve/CVE-2022-37969"><img src="https://intel.neosec.eu/badge/cve/CVE-2022-37969.svg?lang=en" alt="CVE-2022-37969 – NEOSEC Intel" height="20"></a>

What is affected, what to do

Metrics

Response and mitigation

Prioritisation rationale

Immediate response (0-24 h)

Mitigation layers

Detection rules

Detection rules

Classification under NIS2 and CRA

Description

Affected products

Vendors and products

Affected operating systems

Public exploit references

References & sources

Changes to this CVE