CVE-2023-4208 : Security Advisory and Response

This CVE record pertains to a use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component, assigned by Google. It was published on September 6, 2023, and identified as a privilege escalation vulnerability.

Understanding CVE-2023-4208

This CVE-2023-4208 vulnerability involves a use-after-free flaw in the Linux kernel's net/sched: cls_u32 component that can be exploited for local privilege escalation.

What is CVE-2023-4208?

The vulnerability occurs when u32_change() is invoked on an existing filter, leading to a situation where the whole tcf_result struct is copied into the new filter instance. This could result in the referenced class being deleted, allowing for a use-after-free scenario. It is recommended to upgrade past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 to mitigate this issue.

The Impact of CVE-2023-4208

This vulnerability, if exploited, could enable an attacker to locally escalate their privileges within the affected system, posing a significant risk to data confidentiality, integrity, and availability.

Technical Details of CVE-2023-4208

This section provides a deeper dive into the technical aspects of CVE-2023-4208.

Vulnerability Description

The use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component allows for local privilege escalation by manipulating filter instances.

Affected Systems and Versions

The Linux Kernel version 3.18 is affected by this vulnerability, specifically in versions less than 6.5.

Exploitation Mechanism

The vulnerability can be exploited by invoking u32_change() on an existing filter, leading to a use-after-free scenario due to improper handling of filter instances.

Mitigation and Prevention

As CVE-2023-4208 poses a serious security risk, it is crucial to take immediate and proactive steps to mitigate its impact and prevent potential exploitation.

Immediate Steps to Take

Apply the recommended upgrade past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 to address the vulnerability.
Monitor for any signs of unauthorized privilege escalation on the system.

Long-Term Security Practices

Regularly update the Linux kernel to the latest stable version to patch known vulnerabilities.
Implement robust access controls and permissions management to limit potential attack surfaces.

Patching and Updates

Stay informed about security advisories and patches from reputable sources such as the Linux Kernel repositories and apply updates promptly to ensure the system's security integrity.