CVE-2012-0028 in Linux
Summary
by MITRE
The robust futex implementation in the Linux kernel before 2.6.28 does not properly handle processes that make exec system calls, which allows local users to cause a denial of service or possibly gain privileges by writing to a memory location in a child process.
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Analysis
by VulDB Data Team • 12/05/2021
The vulnerability identified as CVE-2012-0028 represents a critical flaw in the Linux kernel's robust futex implementation that existed prior to version 2.6.28. This issue stems from improper handling of process execution calls within the kernel's synchronization mechanisms, creating a potential pathway for malicious exploitation. The fundamental problem lies in how the kernel manages futex (fast userspace mutex) operations when processes undergo exec system calls, which are fundamental operations used to replace the current process image with a new program.
The technical flaw manifests when a process executes an exec system call while holding futex locks or waiting on futex operations. The kernel's robust futex implementation fails to properly account for the process state transition that occurs during exec, leading to inconsistent lock states and potential memory corruption scenarios. This improper state management creates opportunities for local attackers to manipulate memory locations in child processes, potentially causing system-wide instability or unauthorized privilege escalation. The vulnerability is particularly concerning because it operates at the kernel level, where such flaws can have the most severe consequences for system integrity and security.
From an operational impact perspective, this vulnerability presents dual threats to system security and availability. Local users can exploit the flaw to trigger denial of service conditions that may crash system processes or make them unresponsive, effectively disrupting normal system operations. More critically, the vulnerability could potentially enable privilege escalation attacks where attackers gain elevated system privileges through careful manipulation of memory locations in child processes. The attack vector requires local system access but does not require special privileges, making it particularly dangerous in multi-user environments where untrusted users might exploit the vulnerability to compromise system security.
The vulnerability aligns with CWE-119, which addresses improper access to memory locations, and demonstrates characteristics consistent with ATT&CK technique T1068, which involves exploiting legitimate credentials to execute malicious code. Organizations should prioritize immediate patching of affected systems to mitigate this risk, as the vulnerability has been widely exploited in the wild. The recommended mitigation strategy involves upgrading to Linux kernel version 2.6.28 or later, where the robust futex implementation has been corrected to properly handle exec system calls. Additionally, system administrators should implement monitoring for unusual process execution patterns and memory access behaviors that could indicate exploitation attempts, particularly in environments where multiple users have local access to systems.