CVE-2024-49138 in Windows
Summary
by MITRE • 12/12/2024
Windows Common Log File System Driver Elevation of Privilege Vulnerability
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Analysis
by VulDB Data Team • 08/08/2025
This vulnerability resides within the Windows Common Log File System Driver, specifically affecting the clfs.sys component that manages the common log file system used for transactional logging operations across the Windows operating system. The flaw represents a privilege escalation issue that allows unprivileged users to potentially elevate their access rights to system-level privileges. The vulnerability stems from improper validation of input parameters within the driver's handling of certain log file operations, creating a path for malicious code execution with elevated privileges. This type of vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow, though the specific implementation involves improper access control mechanisms within kernel-mode drivers. The Common Log File System serves as a foundational component for various Windows services and applications that require reliable transactional logging, making this vulnerability particularly concerning for system stability and security.
The technical exploitation of this vulnerability occurs when a local attacker can manipulate specific input parameters passed to the clfs.sys driver during log file operations. The flaw allows for arbitrary code execution within the kernel context, bypassing standard user-mode security controls and access restrictions. Attackers can leverage this to gain SYSTEM-level privileges without requiring authentication or prior access to the system. The vulnerability is particularly dangerous because it operates at the kernel level where all security boundaries are effectively bypassed, allowing for complete system compromise. This aligns with ATT&CK technique T1068 which describes the exploitation of legitimate credentials and system privileges to gain elevated access. The implementation involves manipulation of log file structures and transactional operations that are typically handled transparently by the operating system.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise and potential data exfiltration. Once exploited, attackers can modify system files, install persistent backdoors, and access all system resources without detection. The vulnerability affects multiple Windows versions including Windows 10 and Windows 11 across various architectures, making it a widespread concern for enterprise environments. Organizations running servers or systems with elevated privileges are particularly at risk since the vulnerability can be exploited from any local account, regardless of administrative status. The nature of the flaw means that detection is challenging as the exploitation occurs at the kernel level and may not generate typical security event logs. This vulnerability represents a significant threat to the integrity of Windows systems and can be leveraged as a stepping stone for broader network infiltration activities.
Mitigation strategies should focus on immediate patch deployment from Microsoft, as the vendor has released security updates addressing this specific vulnerability. System administrators should implement the principle of least privilege and ensure that local accounts have minimal necessary permissions. Network segmentation and monitoring solutions should be enhanced to detect anomalous kernel-level activities that may indicate exploitation attempts. The implementation of exploit protection features such as Control Flow Guard and Address Space Layout Randomization can provide additional defense-in-depth measures. Organizations should also conduct comprehensive vulnerability assessments to identify systems running older Windows versions that may not have received the applicable patches. Regular security monitoring and incident response procedures should be updated to include detection of kernel-level privilege escalation attempts, with particular attention to unusual log file access patterns and transactional operation anomalies that could indicate exploitation of this vulnerability.