CVE-2012-6539 in Linux
Summary
by MITRE
The dev_ifconf function in net/socket.c in the Linux kernel before 3.6 does not initialize a certain structure, which allows local users to obtain sensitive information from kernel stack memory via a crafted application.
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Analysis
by VulDB Data Team • 01/01/2022
The vulnerability identified as CVE-2012-6539 represents a critical information disclosure flaw within the Linux kernel's networking subsystem. This issue resides in the dev_ifconf function located in the net/socket.c file, which is responsible for handling interface configuration requests. The vulnerability specifically affects Linux kernel versions prior to 3.6, making it a significant concern for systems running older kernel versions. The flaw manifests when the function fails to properly initialize a structure before using it, creating a pathway for unauthorized information extraction.
The technical mechanism behind this vulnerability involves the improper initialization of kernel data structures during network interface configuration operations. When a local user executes a crafted application that invokes the dev_ifconf function, the uninitialized structure contains residual data from previous kernel operations stored in memory. This residual data includes potentially sensitive information that was previously stored in the kernel stack memory, such as cryptographic keys, session tokens, or other confidential system data. The vulnerability is classified as a CWE-457: Use of Uninitialized Variable, which directly relates to the improper handling of memory allocation and initialization within kernel space. The flaw allows attackers to potentially access information that should remain confidential and protected within the kernel's memory space.
The operational impact of CVE-2012-6539 extends beyond simple information disclosure, as it provides local attackers with access to kernel memory contents that could be leveraged for more sophisticated attacks. While the vulnerability requires local system access, it can be particularly dangerous in environments where privilege escalation is possible or when combined with other vulnerabilities. The sensitive data exposed through this flaw could include kernel pointers, configuration data, or other information that might aid in bypassing security mechanisms. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, where attackers might use information disclosure to gain insights into system internals and potentially exploit additional weaknesses. The local nature of the vulnerability means that attackers do not require network access or remote exploitation capabilities, making it particularly concerning for systems where local access is possible.
Mitigation strategies for CVE-2012-6539 primarily focus on kernel version updates and system hardening measures. The most effective remediation is upgrading to Linux kernel version 3.6 or later, where the improper structure initialization has been corrected. Organizations should also implement proper system patch management processes to ensure timely deployment of security updates. Additional defensive measures include monitoring for suspicious network interface configuration activities and implementing least privilege principles to limit local user access. The vulnerability demonstrates the importance of proper memory initialization practices in kernel code development and highlights the need for comprehensive security testing of system-level functions. Network administrators should also consider implementing intrusion detection systems that can identify unusual patterns of network interface configuration requests that might indicate exploitation attempts.