CVE-2025-53147 in Windows
Summary
by MITRE • 08/12/2025
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 11/22/2025
The vulnerability identified as CVE-2025-53147 represents a critical use-after-free flaw within the Windows Ancillary Function Driver for WinSock component, specifically affecting the ws2ifsl.sys driver. This issue arises from improper memory management practices where freed memory blocks are still referenced or accessed by subsequent operations. The vulnerability is particularly concerning because it exists within a core networking component that operates with elevated privileges, creating a significant attack surface for local privilege escalation. The Windows Ancillary Function Driver serves as a crucial interface for socket operations and network functionality, making this flaw potentially devastating for system security. The use-after-free condition occurs when the driver fails to properly invalidate pointers or reset memory references after deallocation, allowing malicious code to manipulate freed memory locations.
The technical exploitation of this vulnerability requires an attacker to first establish a legitimate user session on the target system, as the flaw does not permit remote code execution but rather local privilege escalation. Attackers can leverage the use-after-free condition by crafting specific network operations that trigger the vulnerable code path within the ws2ifsl.sys driver. This typically involves manipulating socket operations or network interface management functions that utilize the affected driver. The flaw stems from inadequate bounds checking and memory management within the driver's handling of network interface objects, where memory allocated for interface structures is freed but references remain accessible. According to CWE-416, this vulnerability maps directly to use-after-free conditions, while the privilege escalation aspect aligns with CWE-269 and CWE-787. The attack vector is classified as local privilege escalation, with potential mappings to ATT&CK technique T1068 (Local Privilege Escalation) and T1548.1 (Abuse Elevation Control Mechanism).
The operational impact of CVE-2025-53147 extends beyond simple privilege escalation, as successful exploitation can enable attackers to gain SYSTEM-level privileges on the affected Windows system. This elevated access allows complete control over system resources, including the ability to modify or delete files, install malicious software, access sensitive data, and potentially establish persistence mechanisms. The vulnerability affects multiple Windows versions including Windows 10, Windows 11, and various server editions, with the severity rating reflecting its potential for system compromise. Organizations running affected systems face significant risk, particularly in environments where users might have legitimate access to network resources. The exploitation process requires minimal privileges initially but results in maximum system control, making this vulnerability particularly dangerous for enterprise environments where user access controls may not be sufficiently strict. Network administrators and security teams must consider this vulnerability as a critical threat requiring immediate attention.
Mitigation strategies for CVE-2025-53147 focus on both immediate patching and operational security measures. Microsoft has released security updates addressing this vulnerability through regular security patches, and organizations should prioritize applying these updates as soon as possible. In environments where patching cannot be immediately implemented, operational controls should include monitoring for unusual network activity, implementing strict user access controls, and employing network segmentation to limit potential exploitation. The vulnerability's nature makes it particularly challenging to defend against through traditional network monitoring, as the attack occurs within the kernel space and may not generate obvious network signatures. Security teams should consider implementing endpoint detection and response solutions that can monitor for suspicious memory access patterns or driver behavior. Additionally, privileged access accounts should be protected through multi-factor authentication, least privilege principles, and regular security audits. The mitigation approach aligns with ATT&CK technique T1078 (Valid Accounts) and emphasizes the importance of principle of least privilege implementation. Organizations should also conduct vulnerability assessments to identify systems running the affected driver and implement comprehensive monitoring for potential exploitation attempts.