CVE-2013-3301 in Linux
Summary
by MITRE
The ftrace implementation in the Linux kernel before 3.8.8 allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact by leveraging the CAP_SYS_ADMIN capability for write access to the (1) set_ftrace_pid or (2) set_graph_function file, and then making an lseek system call.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-2013-3301 represents a critical flaw in the Linux kernel's ftrace functionality that existed prior to version 3.8.8. This issue resides within the kernel's tracing subsystem which is designed to provide detailed runtime profiling and debugging capabilities for system operations. The ftrace implementation enables developers and system administrators to monitor function calls, trace execution paths, and analyze system behavior through various tracing interfaces. The vulnerability specifically affects the handling of certain trace control files that are accessible through the debugfs filesystem, making it exploitable by local users who possess the CAP_SYS_ADMIN capability.
The technical exploitation of this vulnerability occurs through a carefully orchestrated sequence of operations that leverages the CAP_SYS_ADMIN capability to gain write access to specific ftrace control files. Attackers can target either the set_ftrace_pid or set_graph_function files within the ftrace interface, both of which are designed to control process tracing and function graph tracing respectively. Once write access is obtained, the attacker performs an lseek system call against these controlled files, which triggers a NULL pointer dereference within the kernel's ftrace subsystem. This NULL pointer dereference represents a fundamental memory management error that occurs when the kernel attempts to access a memory location that has not been properly initialized or allocated.
The operational impact of this vulnerability extends beyond simple denial of service, though that remains the primary concern. While the most immediate effect is a system crash leading to a denial of service condition, the potential for unspecified other impacts suggests that this vulnerability could potentially be leveraged for more sophisticated attacks. The NULL pointer dereference creates a kernel-level execution fault that typically results in a system panic or kernel oops, effectively crashing the entire operating system. This type of vulnerability is particularly dangerous in production environments where system stability and uptime are critical, as it can be exploited to disrupt services without requiring elevated privileges beyond what is already available to local users with CAP_SYS_ADMIN.
From a cybersecurity perspective, this vulnerability aligns with CWE-476 which describes NULL Pointer Dereference, and represents a classic example of improper input validation in kernel space code. The ATT&CK framework would categorize this vulnerability under the T1068 technique for "Exploitation for Privilege Escalation" since it requires existing privileges but can be used to cause system-wide disruption. The vulnerability demonstrates how seemingly benign kernel interfaces can become attack vectors when proper input validation and error handling are absent. The fact that it requires the CAP_SYS_ADMIN capability for initial access suggests that it is not a direct privilege escalation vector but rather a mechanism for causing system instability that could potentially be combined with other exploits to achieve more severe outcomes.
The mitigation strategy for this vulnerability involves upgrading to Linux kernel version 3.8.8 or later, where the kernel developers have implemented proper input validation and error handling for the affected ftrace control files. System administrators should also consider implementing additional security measures such as restricting access to debugfs filesystem entries and monitoring for unusual lseek operations against ftrace interfaces. The vulnerability highlights the importance of proper kernel security testing and the need for robust input validation even in kernel subsystems that are primarily designed for debugging and development purposes. Organizations should also maintain updated security patches and regularly audit their kernel configurations to prevent exploitation of similar vulnerabilities in other kernel subsystems.