CVE-2008-2251 in Windows
Summary
by MITRE
Double free vulnerability in the kernel in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP1 and SP2, Vista Gold and SP1, and Server 2008 allows local users to gain privileges via a crafted application that makes system calls within multiple threads, aka "Windows Kernel Unhandled Exception Vulnerability." NOTE: according to Microsoft, this is not a duplicate of CVE-2008-4510.
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Analysis
by VulDB Data Team • 05/31/2025
This vulnerability represents a critical double free condition within the Windows kernel that affects multiple versions of Microsoft operating systems including Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP1 and SP2, Vista Gold and SP1, and Server 2008. The flaw manifests when a malicious application exploits a race condition in kernel memory management, specifically during exception handling scenarios where multiple threads attempt to free the same memory block simultaneously. This type of vulnerability falls under CWE-415 which defines double free conditions as a common class of memory corruption vulnerabilities that occur when the same memory location is freed twice, leading to unpredictable behavior and potential exploitation. The vulnerability is particularly dangerous because it operates at the kernel level where privilege escalation opportunities are maximized.
The technical exploitation mechanism involves crafting a malicious application that creates multiple threads within the kernel space, each making system calls that trigger the same memory deallocation path. When the kernel processes these concurrent requests, it fails to properly synchronize access to shared memory structures, resulting in a double free scenario that corrupts the kernel heap. This heap corruption can be leveraged by local attackers to execute arbitrary code with kernel-level privileges, effectively bypassing user-mode protections and gaining complete system control. The vulnerability is categorized as an unhandled exception vulnerability because the kernel does not properly handle certain exception conditions that arise during concurrent memory deallocation operations.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with a reliable path to achieve system compromise without requiring network connectivity or user interaction. Local attackers can exploit this condition to elevate their privileges from standard user level to system administrator level, enabling them to modify system files, install malicious software, access sensitive data, and potentially establish persistent backdoors. The vulnerability affects a broad range of Microsoft operating systems spanning multiple product lines and service packs, making it particularly dangerous for organizations with diverse IT environments. According to industry analysis and Microsoft's own classification, this vulnerability is distinct from CVE-2008-4510, indicating that it represents a separate and independently exploitable flaw in the Windows kernel memory management subsystem.
Mitigation strategies for this vulnerability require immediate patch deployment through Microsoft's security updates, as the flaw cannot be effectively addressed through configuration changes or workarounds. Organizations should prioritize patching across all affected Windows versions, particularly focusing on systems that may be running in privileged environments where the impact of exploitation would be most severe. Additional defensive measures include implementing kernel-mode exploit protection mechanisms, monitoring for unusual memory allocation patterns, and maintaining comprehensive system logging to detect potential exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and kernel-mode exploitation, making it a significant concern for organizations implementing comprehensive threat detection and response strategies.