CVE-2022-24481: Windows 10 Privilege Escalation Vulnerability

CVE-2022-24481 Overview

CVE-2022-24481 is an elevation of privilege vulnerability in the Windows Common Log File System (CLFS) Driver. The flaw affects a broad range of Microsoft Windows desktop and server platforms, including Windows 7 through Windows 11 and Windows Server 2008 through 2022. An authenticated local attacker can exploit the vulnerability to gain SYSTEM-level privileges on a compromised host. Microsoft addressed the issue in its April 2022 Patch Tuesday release. The vulnerability carries a CVSS 3.1 base score of 7.8 and an EPSS probability of 24.904% (96.218 percentile), indicating elevated likelihood of exploitation activity.

Critical Impact

Successful exploitation grants SYSTEM privileges on the local machine, enabling full compromise of confidentiality, integrity, and availability.

Affected Products

• Microsoft Windows 10 (multiple versions including 1607, 1809, 1909, 20H2, 21H1, 21H2) and Windows 11 (x64, ARM64)
• Microsoft Windows 7 SP1, Windows 8.1, and Windows RT 8.1
• Microsoft Windows Server 2008, 2012, 2016, 2019, and 2022

Discovery Timeline

• 2022-04-15 - CVE-2022-24481 published to the National Vulnerability Database
• 2024-11-21 - Last updated in the NVD database

Technical Details for CVE-2022-24481

Vulnerability Analysis

The vulnerability resides in the Common Log File System (CLFS) driver clfs.sys, a kernel-mode component that provides high-performance, transactional log services to Windows user-mode and kernel-mode clients. CLFS parses Base Log File (BLF) container structures that are partially attacker-controllable from user mode. Improper validation of fields in these log structures allows a local user to corrupt kernel memory. The result is an elevation from a standard user context to NT AUTHORITY\SYSTEM. CLFS has been a recurring target for privilege escalation research because of its complex parser surface and kernel attack reach.

Root Cause

Microsoft classifies the issue under NVD-CWE-noinfo, but the vulnerability class is consistent with prior CLFS driver flaws involving unchecked offsets, sizes, or pointer fields inside log container metadata. When the driver processes a malformed log file, it operates on attacker-influenced data without sufficient bounds or type checks, leading to memory corruption in kernel space.

Attack Vector

Exploitation requires local code execution as an authenticated low-privileged user. No user interaction is needed. An attacker crafts a malicious BLF file and invokes CLFS APIs through user-mode interfaces such as CreateLogFile, then triggers operations that drive clfs.sys into the vulnerable code path. The driver corrupts kernel memory and the attacker leverages the primitive to overwrite a token or kernel object, yielding SYSTEM privileges. The technique is commonly chained with remote code execution flaws or post-exploitation tooling delivered through phishing and commodity malware.

No public proof-of-concept or exploit module is referenced in the enriched data for this CVE. Technical details are described in the Microsoft Security Update CVE-2022-24481 advisory.

Detection Methods for CVE-2022-24481

Indicators of Compromise

• Creation of unusual .blf files in user-writable directories such as %TEMP%, %APPDATA%, or C:\Users\Public.
• Unexpected process token elevation where a standard-user process suddenly runs as NT AUTHORITY\SYSTEM.
• Kernel bug checks (BSOD) referencing clfs.sys shortly before or after suspicious user activity.
• Child processes of non-administrative applications spawning cmd.exe, powershell.exe, or LSASS access tools with SYSTEM integrity.

Detection Strategies

• Monitor for handle opens and CreateLogFile/DeviceIoControl calls against \??\CLFS device objects from non-system processes.
• Hunt for processes loading or interacting with CLFS APIs that subsequently exhibit privilege changes within a short time window.
• Correlate Sysmon Event ID 11 (FileCreate) for .blf artifacts with Event ID 1 (ProcessCreate) showing token elevation.
• Apply behavioral identification rules that flag local privilege escalation patterns mapped to MITRE ATT&CK technique T1068.

Monitoring Recommendations

• Forward kernel crash dumps and Windows Error Reporting telemetry centrally to identify repeated clfs.sys faults across endpoints.
• Track Windows Defender and EDR detections tagged as Exploit:Win32/CVE-2022-24481 or generic CLFS exploit families.
• Audit local logon events (Event ID 4624 type 2/10) paired with subsequent SYSTEM-level process creation to surface suspicious escalation sequences.

How to Mitigate CVE-2022-24481

Immediate Actions Required

• Apply the April 2022 Microsoft security updates to all affected Windows desktop and server systems without delay.
• Inventory endpoints running unsupported versions such as Windows 7 SP1 and Windows Server 2008, and prioritize Extended Security Update coverage or decommissioning.
• Restrict local logon and interactive shell access to systems holding sensitive data or domain-administrative roles.
• Verify EDR coverage on all Windows hosts and confirm signature and behavioral content is current.

Patch Information

Microsoft released fixes for CVE-2022-24481 in the April 2022 Patch Tuesday cycle. The authoritative reference is the Microsoft Security Update CVE-2022-24481 guide, which lists the specific KB articles per affected SKU. Administrators should deploy the relevant cumulative update or monthly rollup via Windows Update, WSUS, Microsoft Update Catalog, or their preferred patch management platform.

Workarounds

• No official workaround eliminates the vulnerability; patching is the only complete remediation.
• Reduce exposure by enforcing the principle of least privilege and removing local administrator rights from standard users.
• Deploy application control policies (Windows Defender Application Control, AppLocker) to block untrusted binaries that would deliver the exploit payload.
• Enable attack surface reduction rules and tamper protection on endpoint security tooling to limit post-exploitation actions.

# Verify the CLFS driver version on a Windows host and confirm patch level
powershell -Command "Get-Item C:\Windows\System32\drivers\clfs.sys | Select-Object VersionInfo"

# List installed April 2022 (or later) security updates
wmic qfe list brief /format:table | findstr /I "KB50124"