CVE-2005-0001 in Linux
Summary
by MITRE
Race condition in the page fault handler (fault.c) for Linux kernel 2.2.x to 2.2.7, 2.4 to 2.4.29, and 2.6 to 2.6.10, when running on multiprocessor machines, allows local users to execute arbitrary code via concurrent threads that share the same virtual memory space and simultaneously request stack expansion.
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Analysis
by VulDB Data Team • 06/30/2019
The vulnerability described in CVE-2005-0001 represents a critical race condition within the Linux kernel's page fault handling mechanism that affects multiple kernel versions including 2.2.x through 2.2.7, 2.4.x through 2.4.29, and 2.6.x through 2.6.10. This flaw specifically manifests when the kernel operates on multiprocessor systems where multiple threads can concurrently access shared virtual memory spaces. The race condition occurs during the page fault handling process in the fault.c file, creating a window of opportunity for malicious exploitation that can lead to privilege escalation and arbitrary code execution.
The technical implementation of this vulnerability stems from improper synchronization mechanisms within the kernel's memory management subsystem. When multiple threads attempt to simultaneously expand their stack space while sharing the same virtual memory region, the kernel's page fault handler fails to properly coordinate access to shared memory structures. This race condition allows an attacker to manipulate the timing of page fault occurrences such that the kernel's memory management code executes in an inconsistent state. The flaw is particularly dangerous because it leverages the inherent concurrency of multiprocessor systems to create a scenario where memory allocation and deallocation operations can be interleaved in unexpected ways, leading to memory corruption that can be exploited to gain elevated privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise. Local users who can create concurrent threads sharing virtual memory space can exploit this race condition to execute arbitrary code with kernel-level privileges, effectively bypassing all user-space security controls. This makes the vulnerability particularly dangerous in multi-user environments where untrusted users might be able to create the necessary conditions for exploitation. The vulnerability affects systems running on multiprocessor hardware, meaning that single-core systems are generally not vulnerable, but it creates a significant attack surface in enterprise environments where multiprocessor systems are common. The exploitation requires specific conditions involving concurrent thread execution and shared memory spaces, but once achieved, the consequences are severe enough to allow full system compromise.
Mitigation strategies for CVE-2005-0001 primarily focus on kernel updates and system hardening measures. The most effective solution involves applying the appropriate kernel patches released by the Linux kernel development team, which address the race condition in the page fault handling code by implementing proper synchronization mechanisms. System administrators should ensure that all affected kernel versions are updated promptly, as this vulnerability has been widely exploited in the wild. Additionally, implementing proper access controls and limiting the ability of untrusted users to create concurrent threads with shared memory spaces can reduce the attack surface. The vulnerability aligns with CWE-362 which identifies race conditions as a common weakness in concurrent programming, and it can be mapped to ATT&CK technique T1068 which covers privilege escalation through local exploits. Organizations should also consider implementing monitoring for suspicious concurrent thread behavior and memory allocation patterns that might indicate exploitation attempts.