CVE-2024-56569 is a vulnerability identified in the Linux kernel's ftrace subsystem, specifically related to the stack_trace_filter functionality. The issue arises when the command echo "write*:mod:ext3" > /sys/kernel/tracing/stack_trace_filter is executed. This command uses the 'mod' filter in the stack_trace_filter, which is intended to filter stack traces by kernel modules. However, a regression bug causes a null pointer dereference due to an unhandled corner case in the module command processing. Although a prior commit (0f17976568b3f) addressed part of this problem, it did not fully resolve the issue, leaving a scenario where the kernel can still crash. The vulnerability results in a kernel panic or crash, causing a denial of service (DoS) condition. The affected versions are specific Linux kernel commits identified by the hash 04ec7bb642b77374b53731b795b5654b5aff1c00, indicating a narrow range of kernel builds. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. The vulnerability requires local access to execute the command, implying that an attacker must have the ability to run commands on the affected system, either via direct access or through some form of privilege escalation. The impact is primarily on system availability due to kernel crashes triggered by malformed input to the ftrace subsystem.

For European organizations, the impact of CVE-2024-56569 centers on potential denial of service conditions on Linux-based systems. Since Linux is widely used in servers, cloud infrastructure, and embedded devices across Europe, this vulnerability could disrupt critical services if exploited. Systems running affected kernel versions may experience unexpected crashes, leading to downtime, loss of productivity, and potential cascading failures in dependent services. Organizations relying on Linux for web hosting, database servers, or network appliances could face service interruptions. Although the vulnerability does not directly expose confidentiality or integrity risks, the availability impact can be significant, especially for sectors requiring high uptime such as finance, healthcare, telecommunications, and government services. The requirement for local command execution limits remote exploitation, but insider threats or attackers who have gained initial access could leverage this vulnerability to cause disruption. The absence of known exploits reduces immediate risk, but the presence of a kernel-level DoS vulnerability warrants prompt attention to prevent potential abuse.

To mitigate CVE-2024-56569, European organizations should: 1) Identify and inventory Linux systems running affected kernel versions, focusing on those with kernel commit hashes matching or close to 04ec7bb642b77374b53731b795b5654b5aff1c00. 2) Apply the latest kernel patches or updates from trusted Linux distributions that address this vulnerability as soon as they become available. 3) Restrict access to the /sys/kernel/tracing/stack_trace_filter interface by enforcing strict permissions and limiting which users or processes can write to this file, reducing the risk of unauthorized command execution. 4) Monitor system logs and kernel messages for signs of crashes or suspicious activity related to ftrace or stack_trace_filter usage. 5) Implement robust access controls and privilege separation to minimize the risk of attackers gaining local command execution capabilities. 6) For critical systems, consider deploying kernel live patching solutions that can apply fixes without requiring system reboots, minimizing downtime. 7) Educate system administrators about this vulnerability and the importance of controlling access to kernel tracing facilities. These steps go beyond generic advice by focusing on controlling the specific interface involved and prioritizing patch management for affected kernel versions.