CVE-2011-1598 in Linux
Summary
by MITRE
The bcm_release function in net/can/bcm.c in the Linux kernel before 2.6.39-rc6 does not properly validate a socket data structure, which allows local users to cause a denial of service (NULL pointer dereference) or possibly have unspecified other impact via a crafted release operation.
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Analysis
by VulDB Data Team • 11/07/2021
The vulnerability described in CVE-2011-1598 resides within the Linux kernel's CAN (Controller Area Network) subsystem, specifically in the bcm_release function located in net/can/bcm.c. This flaw represents a classic case of improper input validation that can lead to system instability and potential security implications. The CAN protocol is widely used in automotive and industrial control systems for communication between embedded devices, making this vulnerability particularly concerning for environments where kernel stability is critical. The vulnerability affects Linux kernel versions prior to 2.6.39-rc6, indicating it was present for several years and likely exploited in various scenarios.
The technical flaw stems from inadequate validation of socket data structures within the bcm_release function, which is responsible for cleaning up and releasing CAN socket resources. When a user-space application attempts to release a CAN socket, the kernel's bcm_release function fails to properly verify the integrity of the socket structure before attempting to access its components. This validation gap creates a condition where a malicious local user can craft a specific release operation that results in a NULL pointer dereference. The vulnerability operates at the kernel level, meaning that exploitation does not require special privileges beyond local access, making it particularly dangerous in multi-user environments where local attackers could leverage this weakness to disrupt system operations.
The operational impact of this vulnerability manifests primarily as a denial of service condition, where the kernel crashes due to the NULL pointer dereference, causing the system to become unresponsive or requiring a reboot to restore normal operation. However, the description also hints at "unspecified other impact," suggesting that the vulnerability could potentially be exploited for more sophisticated attacks beyond simple DoS. This could include privilege escalation or information disclosure, though such exploitation would require additional attack vectors or more complex exploitation techniques. The nature of the vulnerability aligns with CWE-476, which describes NULL Pointer Dereference, and represents a fundamental security weakness in kernel memory management. From an ATT&CK perspective, this vulnerability maps to privilege escalation and denial of service techniques, as it allows local users to compromise system availability.
The mitigation strategy for CVE-2011-1598 involves upgrading to Linux kernel version 2.6.39-rc6 or later, where the vulnerability has been patched through proper validation of socket data structures before dereferencing. System administrators should prioritize this update, especially in environments where CAN communication is utilized, such as automotive systems, industrial control networks, and embedded devices. Additionally, organizations should implement proper access controls and monitoring to detect potential exploitation attempts, as the vulnerability can be triggered through legitimate socket operations. The patch addresses the root cause by ensuring that the bcm_release function validates socket structure integrity before attempting to access any socket members, preventing the NULL pointer dereference condition that leads to system instability. This vulnerability underscores the importance of proper kernel input validation and demonstrates how seemingly minor flaws in kernel subsystems can have significant operational impacts in critical infrastructure environments.