CVE-2023-4134: Use-After-Free Vulnerability in Linux Kernel's cyttsp4_core Driver

A new vulnerability, CVE-2023-4134, has been discovered in the Linux kernel affecting the cyttsp4_core driver. This issue is a use-after-free vulnerability, which if exploited, could allow a local user to crash the system and cause a denial of service. This blog post will provide an in-depth look at the vulnerability, the code snippet where the issue resides, links to original references, and exploit details.

The Vulnerability

The cyttsp4_core driver in the Linux kernel has been found to have a use-after-free vulnerability. Specifically, this issue occurs in the device cleanup routine due to a potential rearming of the watchdog_timer from the workqueue. A local attacker could exploit this vulnerability by causing a denial-of-service (DoS) attack and crashing the system.

The following code snippet shows the affected part of the cyttsp4_core driver in the Linux kernel

static void cyttsp4_watchdog_work(struct work_struct *work)
{
    struct cyttsp4_core_data *cd =
            container_of(work, struct cyttsp4_core_data, watchdog_work.work);
    ...
    queue_delayed_work(cd->cyttsp4_wq, &cd->watchdog_work, cd->watchdog_interval);
}

This function schedules the watchdog_work workqueue task, which may be re-armed during the device cleanup process. When re-armed, the use-after-free vulnerability may be triggered.

Original References

The vulnerability was first reported in the Linux kernel list, where developers discussed the issue and its impact. Additional details about the vulnerability are available in the following links:

- Linux Kernel Mailing List: Link to LKML Discussion
- National Vulnerability Database: CVE-2023-4134

Exploit Details

To exploit this vulnerability, an attacker would need local access to the target system. They could then craft a malicious kernel module or utilize other kernel programming interfaces to re-arm the watchdog_work timer during the device cleanup process. In doing so, the attacker could cause the system to crash and cause a denial-of-service (DoS) attack.

Proof of Concept

There is currently no public proof-of-concept code available that demonstrates successful exploitation of this vulnerability. However, security researchers may release one in the future to help validate the existence of the vulnerability and develop defense mechanisms.

Mitigation Steps

To mitigate this vulnerability, users are urged to apply the latest Linux kernel updates and patches as soon as they become available. In addition, system administrators should restrict local access to trusted users and ensure that security best practices are followed to minimize the potential attack surface.

In conclusion, CVE-2023-4134 is a use-after-free vulnerability found in the Linux kernel's cyttsp4_core driver. It could allow a local user to crash the system and cause a denial of service. Users should remain vigilant, be aware of this vulnerability's implications, and take steps to ensure their systems are protected against potential attacks.

Timeline

Published on: 11/14/2024 10:44:42 UTC