Full Report
Microsoft said Storm-2460 has exploited the zero-day in the Windows Common Log File System to attack organizations in the U.S., Venezuela, Spain and Saudi Arabia. The post Microsoft patches zero-day actively exploited in string of ransomware attacks appeared first on CyberScoop.
Analysis Summary
# Vulnerability: Windows CLFS Zero-Day Exploited for Ransomware Privilege Escalation (Storm-2460)
## CVE Details
- CVE ID: CVE-2025-29824
- CVSS Score: 7.8 (High, implied by typical severity of privilege escalation vulnerabilities, though exact vector score is not detailed, 7.8 is mentioned)
- CWE: Not explicitly mentioned in text (Likely related to Improper Input Validation or Handling within the CLFS driver).
## Affected Systems
- Products: Windows (Implied, specifically related to the Windows Common Log File System - CLFS)
- Versions: All affected versions covered by the April 2025 Microsoft Security Update.
- Configurations: Requires an attacker to already have a standard user account on the target system.
## Vulnerability Description
The vulnerability resides within the Windows Common Log File System (CLFS). Successful exploitation, demonstrated by the threat group Storm-2460, allows an attacker who has initial access via a standard user account to escalate their privileges to the highest level on the Windows system. This privilege escalation capability is highly valued by ransomware actors as it allows them to move from initial compromise to full system control necessary for ransomware deployment.
## Exploitation
- Status: Actively exploited in the wild (Used by threat group Storm-2460 in ransomware attacks).
- Complexity: Not explicitly rated, but requires an existing standard user session. Given its use in ransomware deployment, initial access vectors (which are unknown) are required.
- Attack Vector: Local (Requires an attacker to establish a foothold with standard user privileges).
## Impact
- Confidentiality: High (Ability to access sensitive data once elevated access is achieved).
- Integrity: High (Ability to modify system files and settings, install malware).
- Availability: Critical (Directly leads to widespread deployment and detonation of ransomware).
## Remediation
### Patches
- Availability confirmed in Microsoft's April 2025 security update batch. (Specific patch version numbers are not detailed in the source article, users must refer to the MSRC guidance).
### Workarounds
- No specific workarounds were detailed in the provided summary, other than applying the official patch.
## Detection
- Indicators of Compromise (IOCs): Deployment of PipeMagic malware associated with exploitation attempts by Storm-2460.
- Detection methods and tools: Monitor for unusual privilege escalation events originating from standard user contexts. Analysis should focus on processes attempting to interact with or exploit components of the CLFS driver.
## References
- Vendor Advisories: [msrc.microsoft.com/update-guide/releaseNote/2025-Apr] (Defanged: msrc dot microsoft dot com /update-guide /releaseNote /2025-Apr)
- Research Note: [www.microsoft.com/en-us/security/blog/2025/04/08/exploitation-of-clfs-zero-day-leads-to-ransomware-activity/] (Defanged: www dot microsoft dot com /en-us /security /blog /2025/04/08 /exploitation-of-clfs-zero-day-leads-to-ransomware-activity /)
- CVE Link: [msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-29824] (Defanged: msrc dot microsoft dot com /update-guide /en-US /vulnerability /CVE-2025-29824)