CVE-2012-2390 in Linux
Summary
by MITRE
Memory leak in mm/hugetlb.c in the Linux kernel before 3.4.2 allows local users to cause a denial of service (memory consumption or system crash) via invalid MAP_HUGETLB mmap operations.
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Analysis
by VulDB Data Team • 12/03/2021
The vulnerability identified as CVE-2012-2390 represents a critical memory management flaw within the Linux kernel's huge page implementation. This issue resides in the mm/hugetlb.c file and affects kernel versions prior to 3.4.2, creating a pathway for local attackers to exploit memory handling mechanisms through malformed MAP_HUGETLB memory mapping operations. The vulnerability stems from inadequate validation of memory mapping parameters during huge page allocation processes, specifically when handling memory regions that should be allocated using huge page mappings.
The technical exploitation of this vulnerability occurs when a local user performs invalid MAP_HUGETLB mmap operations that bypass proper parameter validation within the kernel's huge page subsystem. During these operations, the kernel fails to properly release memory resources when encountering malformed mapping requests, leading to progressive memory consumption that can eventually exhaust available system memory. The flaw manifests as a memory leak because the kernel allocates memory for huge page structures but fails to deallocate them when the mapping operations are invalid or malformed, creating a gradual degradation of system resources.
This vulnerability directly impacts system stability and availability by enabling a local denial of service condition that can either consume excessive memory resources or trigger system crashes. The memory leak accumulation occurs during repeated invalid MAP_HUGETLB operations, where each failed mapping attempt contributes to unaccounted memory consumption that progressively reduces available system resources. When the system reaches memory exhaustion, it can either become unresponsive due to memory pressure or experience kernel crashes that result in complete system downtime. The impact is particularly severe in environments where memory resources are constrained or where multiple processes repeatedly attempt invalid huge page mappings.
The operational implications of CVE-2012-2390 extend beyond simple resource exhaustion, as it represents a fundamental flaw in kernel memory management that can be exploited by any local user with sufficient privileges to execute mmap operations. This vulnerability aligns with CWE-401, which describes improper handling of memory allocation and deallocation in software systems, specifically focusing on memory leaks that occur due to failure to release allocated resources. The attack vector is classified as local privilege escalation in the context of the ATT&CK framework, specifically mapping to the technique of privilege escalation through resource consumption. Organizations should prioritize immediate patching of affected kernel versions to address this vulnerability, as the memory leak can be exploited iteratively to cause sustained system instability without requiring elevated privileges beyond basic user access.
Mitigation strategies for this vulnerability center on kernel version updates to 3.4.2 or later, which contain the necessary patches to properly validate MAP_HUGETLB operations and ensure correct memory deallocation. System administrators should implement comprehensive monitoring of memory usage patterns to detect unusual consumption that might indicate exploitation attempts. Additionally, security hardening measures including restrictive memory mapping permissions and process isolation can reduce the attack surface for potential exploitation. The vulnerability highlights the importance of proper resource management in kernel space operations and demonstrates how seemingly minor validation flaws can lead to significant system stability issues. Organizations should also consider implementing automated patch management systems to ensure timely deployment of kernel security updates, as this vulnerability affects the core memory management functionality of the Linux operating system and represents a persistent risk to system availability.