CVE-2012-3511 in Linux
Summary
by MITRE
Multiple race conditions in the madvise_remove function in mm/madvise.c in the Linux kernel before 3.4.5 allow local users to cause a denial of service (use-after-free and system crash) via vectors involving a (1) munmap or (2) close system call.
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Analysis
by VulDB Data Team • 03/27/2021
The vulnerability identified as CVE-2012-3511 represents a critical race condition flaw within the Linux kernel's memory management subsystem, specifically in the madvise_remove function located in mm/madvise.c. This vulnerability affects Linux kernel versions prior to 3.4.5 and exposes systems to potential denial of service attacks through use-after-free conditions and system crashes. The flaw arises from insufficient synchronization mechanisms during memory management operations, creating opportunities for malicious local users to exploit temporal inconsistencies in the kernel's memory handling routines.
The technical implementation of this vulnerability stems from race conditions in how the kernel processes memory advice operations, particularly when handling madvise system calls in conjunction with memory mapping operations. When a process invokes madvise with MADV_REMOVE flags, the kernel must coordinate between multiple memory management components to properly handle memory deallocation. The race condition occurs when concurrent operations involving munmap or close system calls interfere with the madvise_remove function's execution, leading to improper memory state management. This temporal inconsistency allows attackers to manipulate the kernel's memory management structures in ways that result in freed memory being accessed after deallocation, creating use-after-free scenarios that can trigger kernel panic or system crashes.
The operational impact of CVE-2012-3511 extends beyond simple denial of service, as it represents a fundamental flaw in kernel memory management that can be exploited by local attackers with minimal privileges. The vulnerability affects systems running Linux kernel versions before 3.4.5, making it particularly concerning for organizations maintaining older kernel versions or those that have not applied security patches. Attackers can leverage this vulnerability to cause system instability, potentially leading to complete system crashes that require manual rebooting and resulting in service disruption. The attack vector requires local access to the system, but the potential for system-wide impact makes this vulnerability particularly dangerous in multi-user environments where privilege escalation might be possible through other attack vectors.
From a cybersecurity perspective, this vulnerability aligns with CWE-362, which describes race conditions in kernel memory management operations. The flaw also maps to ATT&CK technique T1499.004, which involves network disruption through system resource exhaustion or kernel-level attacks. The vulnerability demonstrates how seemingly minor synchronization issues in kernel code can result in catastrophic system failures, highlighting the critical importance of proper locking mechanisms and atomic operations in kernel space. Organizations should prioritize patching affected systems to address this vulnerability, as the window for exploitation remains open for unpatched systems. The remediation approach involves upgrading to Linux kernel version 3.4.5 or later, where the race condition has been properly addressed through enhanced synchronization mechanisms and proper memory state management during madvise operations.