CVE-2012-6541 in Linux
Summary
by MITRE
The ccid3_hc_tx_getsockopt function in net/dccp/ccids/ccid3.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-2012-6541 resides within the Linux kernel's implementation of the DCCP protocol stack, specifically in the ccid3_hc_tx_getsockopt function located in net/dccp/ccids/ccid3.c. This flaw represents a classic information disclosure vulnerability that affects Linux kernel versions prior to 3.6, creating a significant security risk for systems utilizing the DCCP protocol. The issue stems from improper initialization of a kernel data structure during socket option retrieval operations, which can lead to the exposure of sensitive data residing in kernel memory space.
The technical root cause of this vulnerability lies in the failure to properly initialize a structure within the ccid3_hc_tx_getsockopt function. When a local application makes a crafted socket option request, the function processes the request without adequately clearing or initializing the target structure before populating it with data. This incomplete initialization means that portions of the structure may retain values from previous operations or contain uninitialized memory contents from the kernel stack. The vulnerability is classified under CWE-457 as "Use of Uninitialized Variable" and operates as a form of information disclosure through memory leakage.
The operational impact of this vulnerability is particularly concerning for local attackers who can leverage it to extract sensitive information from kernel memory. This includes potentially critical data such as cryptographic keys, session tokens, or other confidential information that may be present in the kernel stack at the time of the function call. The attack vector requires local system access, making it a privilege escalation concern that can be exploited by malicious users with limited system privileges to gain access to otherwise protected kernel memory contents. This vulnerability affects systems running Linux kernel versions 3.5 and earlier, creating a substantial risk for organizations that have not updated their kernel implementations.
The implications of this vulnerability extend beyond simple information disclosure, as the leaked kernel memory may contain data that could be used to facilitate further attacks or compromise system integrity. Attackers could potentially use the leaked information to perform more sophisticated attacks such as kernel exploitation or to bypass security mechanisms that rely on the confidentiality of kernel memory contents. This vulnerability aligns with ATT&CK technique T1005 as "Data from Local System" and demonstrates how seemingly minor initialization flaws in kernel code can result in significant security implications. The vulnerability underscores the critical importance of proper memory management and initialization practices in kernel space code, where even small oversights can lead to substantial information leakage.
Mitigation of this vulnerability requires immediate kernel updates to version 3.6 or later, where the initialization issue has been addressed. System administrators should prioritize patching affected systems and ensure that all kernel components are up to date with the latest security fixes. Additionally, monitoring for suspicious socket option requests and implementing proper access controls for local users can help reduce the risk of exploitation. Organizations should also consider implementing kernel hardening measures and regularly auditing their kernel configurations to prevent similar issues from arising in the future. The fix implemented in kernel version 3.6 specifically addresses the uninitialized structure issue by ensuring proper initialization of the affected data structures before they are populated with information from kernel memory.