CVE-2012-6546 in Linux
Summary
by MITRE
The ATM implementation in the Linux kernel before 3.6 does not initialize certain structures, 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-2012-6546 represents a critical information disclosure flaw within the Linux kernel's ATM (Asynchronous Transfer Mode) subsystem. This issue affects kernel versions prior to 3.6 and stems from improper initialization of kernel data structures during ATM socket operations. The flaw exists in the way the kernel handles memory allocation and initialization for ATM protocol implementations, creating a pathway for local attackers to access sensitive data that should remain protected within kernel memory spaces.
The technical root cause of this vulnerability lies in the insufficient initialization of kernel structures used by the ATM subsystem. When applications create ATM sockets or perform operations within this protocol framework, certain memory regions containing kernel data structures are not properly cleared or initialized before use. This incomplete initialization leaves residual data from previous operations or kernel memory contents exposed, allowing malicious applications to read kernel stack memory through carefully crafted system calls or socket operations. The vulnerability is classified as a memory exposure issue that directly violates fundamental security principles of kernel memory management and information hiding.
From an operational perspective, this vulnerability poses significant risks to systems running affected kernel versions. Local attackers with minimal privileges can exploit this flaw to extract sensitive information such as cryptographic keys, session tokens, passwords, or other confidential data that may have resided in the kernel memory spaces. The impact extends beyond simple information disclosure, as the leaked data could potentially be used to escalate privileges, conduct further attacks, or compromise system integrity. The vulnerability affects any system utilizing ATM networking capabilities or having the ATM kernel modules loaded, making it particularly concerning for enterprise environments where kernel-level security is paramount.
The exploitation of CVE-2012-6546 aligns with several ATT&CK techniques including privilege escalation through kernel exploits and credential access via information discovery. This vulnerability demonstrates a classic case of improper initialization leading to information exposure, which corresponds to CWE-248, or "Uncaught Exception," and CWE-457, "Use of Uninitialized Variable." Organizations should immediately apply kernel updates to version 3.6 or later where this vulnerability has been patched. System administrators should also consider implementing additional monitoring for unusual memory access patterns and ensure that ATM functionality is disabled if not required. The patch addresses the core initialization issue by ensuring all kernel structures are properly cleared before use, preventing information leakage from kernel memory spaces.