Full Report
Microsoft has released security fixes to address a massive set of 126 flaws affecting its software products, including one vulnerability that it said has been actively exploited in the wild. Of the 126 vulnerabilities, 11 are rated Critical, 112 are rated Important, and two are rated Low in severity. Forty-nine of these vulnerabilities are classified as privilege escalation, 34 as remote code
Analysis Summary
# Vulnerability: Actively Exploited Use-After-Free in Windows CLFS Driver
## CVE Details
- CVE ID: CVE-2025-29824
- CVSS Score: 7.8 (High)
- CWE: Use-After-Free (Implicit)
## Affected Systems
- Products: Windows (specifically noted for Windows 10 32-bit and 64-bit)
- Versions: Windows 10 (Versions not explicitly listed, but explicitly discussed as lacking a patch)
- Configurations: Local access required.
## Vulnerability Description
The vulnerability is an Elevation of Privilege (EoP) flaw residing in the Windows Common Log File System (CLFS) Driver. It stems from a **use-after-free** scenario in memory management. Under specific memory manipulation conditions, an attacker can trigger this flaw to execute code with the highest privilege level on the system (SYSTEM). Exploitation requires only local access, not administrative privileges.
## Exploitation
- Status: **Exploited in the wild** (Linked to ransomware attacks against a small number of targets). CISA has added it to the KEV catalog.
- Complexity: Not explicitly detailed, but confirmed exploitation suggests **Low** or **Medium** complexity for sophisticated actors.
- Attack Vector: **Local**
## Impact
- Confidentiality: **High** (SYSTEM-level access can lead to sensitive data access)
- Integrity: **High** (SYSTEM-level attacker can modify system settings and tamper with security features)
- Availability: **High** (SYSTEM-level attacker can install malicious software or compromise stability)
## Remediation
### Patches
Microsoft released security fixes in its April 2025 update cycle. **Note:** The article explicitly states that at the time of research, **no patch had been released for Windows 10 32-bit or 64-bit systems**, creating a critical gap. Security patches for other affected products and the resolution for other Windows versions should be sought via the linked MSRC resource.
### Workarounds
No specific workarounds were detailed in the provided context. Applying available vendor patches is the primary mitigation.
## Detection
- Indicators of Compromise: Active exploitation has been linked to **ransomware attacks**. Monitoring for unexpected privilege escalation to SYSTEM or suspicious activity involving the CLFS driver during post-compromise persistence/lateral movement attempts is crucial.
- Detection methods and tools: Ensure systems are monitored for IOCs relating to known ransomware groups that leverage this technique. Checking for successful exploitation attempts against the CLFS driver.
## References
- Vendor Advisories: msr/c/update-guide/releaseNote/2025-apr
- CISA KEV: cisa/gov/news-events/alerts/2025/04/08/cisa-adds-two-known-exploited-vulnerabilities-catalog