CVE-2023-2163 : Security Advisory and Response

This CVE entry was assigned by Google on April 18, 2023, and was published on September 20, 2023. It involves a critical vulnerability in the Linux Kernel related to incorrect verifier pruning logic, potentially leading to arbitrary read/write capabilities, lateral privilege escalation, and container escape.

Understanding CVE-2023-2163

This vulnerability, identified in the Linux Kernel, poses a severe threat by allowing attackers to exploit flawed verifier pruning logic to gain unauthorized access, manipulate kernel memory, escalate privileges, and escape containers.

What is CVE-2023-2163?

The CVE-2023-2163 vulnerability arises from incorrect verifier pruning in Berkeley Packet Filter (BPF) in Linux Kernel versions greater than or equal to 5.4. It results in unsafe code paths being incorrectly marked as safe, enabling arbitrary read/write actions in kernel memory, lateral privilege escalation, and potential container escape.

The Impact of CVE-2023-2163

The impact of this vulnerability, categorized under CAPEC-233 (Privilege Escalation), is considered critical. It can lead to high confidentiality and integrity impacts, with attackers able to exploit the flaw remotely without user interaction, significantly increasing the severity of potential breaches.

Technical Details of CVE-2023-2163

The vulnerability is scored 10 out of 10 in severity according to the CVSS v3.1 scoring system, denoting a critical flaw with a low attack complexity. The attack vector primarily involves network-based attacks, and successful exploitation can result in arbitrary read/write capabilities in kernel memory, compromising system integrity and confidentiality.

Vulnerability Description

The CVE-2023-2163 vulnerability stems from incorrect verifier pruning in BPF in Linux Kernel versions greater than or equal to 5.4, allowing attackers to exploit unsafe code paths, leading to unauthorized memory access, lateral privilege escalation, and potential container escape.

Affected Systems and Versions

The vulnerability affects Linux Kernel versions from 5.4 onwards. Specifically, the flaw impacts versions prior to commit 71b547f561247897a0a14f3082730156c0533fed in the Git repository. Systems running affected versions are at risk of exploitation if not promptly patched.

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting malicious inputs to leverage the incorrect verifier pruning logic in BPF, allowing them to manipulate kernel memory, escalate privileges, and potentially evade container security measures, posing a significant threat to system security.

Mitigation and Prevention

Addressing the CVE-2023-2163 vulnerability requires immediate action to mitigate the risks associated with arbitrary read/write capabilities, privilege escalation, and container escape scenarios.

Immediate Steps to Take

Implement patches provided by Linux Kernel developers to address the vulnerability in affected versions.
Monitor system logs for any suspicious activities that could indicate exploitation attempts.
Restrict network access to vulnerable systems to reduce the risk of remote attacks.

Long-Term Security Practices

Regularly update and patch system software to ensure the latest security fixes are applied.
Conduct vulnerability assessments and penetration testing to uncover and address potential security weaknesses proactively.
Stay informed about emerging threats and security best practices to enhance overall system resilience.

Patching and Updates

Users and administrators are advised to apply the necessary patches released by the Linux Kernel maintainers to mitigate the CVE-2023-2163 vulnerability. Keeping systems up to date with the latest security updates is crucial in maintaining a secure and resilient environment.