CVE-2012-6544 in Linux
Summary
by MITRE
The Bluetooth protocol stack in the Linux kernel before 3.6 does not properly initialize certain structures, which allows local users to obtain sensitive information from kernel stack memory via a crafted application that targets the (1) L2CAP or (2) HCI implementation.
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Analysis
by VulDB Data Team • 01/01/2022
The vulnerability identified as CVE-2012-6544 represents a critical information disclosure flaw within the Linux kernel's Bluetooth protocol stack implementation. This issue affects kernel versions prior to 3.6 and stems from inadequate initialization of memory structures during Bluetooth protocol processing. The vulnerability specifically impacts two key components of the Bluetooth stack: the L2CAP (Logical Link Control and Adaptation Protocol) implementation and the HCI (Host Controller Interface) implementation. These components handle the core communication protocols that enable Bluetooth device connectivity and data transfer within Linux systems.
The technical root cause of this vulnerability lies in the improper initialization of kernel memory structures that are used during Bluetooth protocol processing. When a crafted application attempts to interact with the Bluetooth stack through either L2CAP or HCI interfaces, the uninitialized memory regions contain residual data from previous operations or kernel stack contents. This incomplete initialization creates a situation where sensitive information from kernel memory, including potential cryptographic keys, session data, or other confidential information, can be inadvertently exposed to local users. The vulnerability operates at the kernel level, making it particularly dangerous as it bypasses normal user-space security boundaries and directly accesses privileged memory regions.
The operational impact of CVE-2012-6544 extends beyond simple information disclosure, as it creates potential attack vectors for local privilege escalation and credential harvesting. A local attacker with access to the system can exploit this vulnerability to extract sensitive kernel memory contents, which may include session keys, cryptographic material, or other confidential data that could be leveraged for further attacks. This weakness particularly affects systems running older kernel versions where Bluetooth functionality is enabled, making it a significant concern for enterprise environments and embedded systems that rely on Linux kernel Bluetooth implementations. The vulnerability demonstrates a clear violation of the principle of least privilege and proper memory initialization practices that are fundamental to secure kernel design.
Mitigation strategies for CVE-2012-6544 primarily focus on kernel version upgrades to 3.6 or later, where the memory initialization issues have been addressed through proper kernel patches. System administrators should prioritize updating their kernel versions to eliminate exposure to this vulnerability, particularly in environments where Bluetooth functionality is actively used. Additionally, implementing proper access controls and limiting local user privileges can reduce the attack surface, though this does not eliminate the underlying vulnerability. The fix typically involves ensuring that all kernel data structures are properly initialized before being used, which aligns with the common weakness enumeration CWE-121, which addresses improper initialization of memory. This vulnerability also relates to ATT&CK technique T1068, which covers local privilege escalation through kernel vulnerabilities, and T1552, which encompasses credential access through memory dumping techniques. Organizations should also consider implementing monitoring solutions to detect anomalous Bluetooth protocol usage patterns that might indicate exploitation attempts.