CVE-2011-2182 in Linux
Summary
by MITRE
The ldm_frag_add function in fs/partitions/ldm.c in the Linux kernel before 2.6.39.1 does not properly handle memory allocation for non-initial fragments, which might allow local users to conduct buffer overflow attacks, and gain privileges or obtain sensitive information, via a crafted LDM partition table. NOTE: this vulnerability exists because of an incomplete fix for CVE-2011-1017.
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Analysis
by VulDB Data Team • 12/03/2021
The vulnerability described in CVE-2011-2182 represents a critical buffer overflow flaw within the Linux kernel's Logical Disk Manager partition handling code. This issue affects the ldm_frag_add function located in fs/partitions/ldm.c, which processes Logical Disk Manager partition tables used primarily on Windows systems. The vulnerability emerges from improper memory allocation handling specifically for non-initial fragments within LDM partition structures, creating a scenario where maliciously crafted partition tables can trigger memory corruption. The flaw is particularly concerning because it allows local attackers with access to the system to potentially execute arbitrary code with elevated privileges, effectively bypassing standard security boundaries and potentially leading to complete system compromise.
The technical root cause of this vulnerability stems from inadequate bounds checking and memory management within the ldm_frag_add function. When processing LDM partition tables, the kernel fails to properly validate the size and structure of non-initial fragments, leading to situations where allocated memory buffers may be insufficient for the actual data being processed. This memory allocation deficiency creates a classic buffer overflow condition that can be exploited to overwrite adjacent memory locations, potentially corrupting kernel data structures or even executing malicious code. The vulnerability manifests specifically when the kernel encounters crafted LDM partition tables that manipulate fragment size parameters in ways that exceed the allocated buffer boundaries. This flaw directly aligns with CWE-121, which describes buffer overflow conditions where insufficient space is allocated for data, and CWE-122, which covers heap-based buffer overflows that occur when insufficient memory is allocated for buffers.
The operational impact of CVE-2011-2182 extends beyond simple privilege escalation to encompass potential information disclosure and system stability issues. Local attackers can leverage this vulnerability to gain root-level privileges, effectively bypassing the kernel's security mechanisms and gaining complete control over the affected system. The attack vector requires local access to the system since the vulnerability exists within the kernel's partition handling code, making it accessible only to users who already have some level of system access. However, once exploited, the consequences are severe as the attacker can manipulate kernel memory, read sensitive data from memory locations, and potentially establish persistent backdoors. The vulnerability's existence as a regression from an incomplete fix for CVE-2011-1017 indicates that the initial remediation was insufficient, leaving the system exposed to the same class of memory handling errors.
Mitigation strategies for CVE-2011-2182 primarily focus on immediate kernel updates and system hardening measures. The most effective solution involves upgrading to Linux kernel version 2.6.39.1 or later, which contains the complete fix for this vulnerability. Organizations should prioritize patching systems running affected kernel versions to prevent exploitation. Additionally, system administrators should implement strict access controls and monitor for unusual system behavior that might indicate exploitation attempts. The vulnerability's nature as a kernel-level buffer overflow suggests that traditional user-space protections like ASLR and DEP may be insufficient for complete protection. Security measures should include monitoring for malformed partition table access attempts and implementing network segmentation to limit local access privileges. This vulnerability demonstrates the importance of thorough regression testing in security patches and highlights the need for comprehensive memory safety validation in kernel subsystems. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting kernel-level exploits that leverage memory corruption to gain elevated system privileges.