CVE-2023-6111 Explained : Impact and Mitigation

This CVE-2023-6111 pertains to a use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component with the potential for local privilege escalation.

Understanding CVE-2023-6111

The vulnerability in focus involves a flaw in the function

nft_trans_gc_catchall

within the nf_tables component of the Linux kernel. This flaw allows an attacker to exploit the system to achieve local privilege escalation.

What is CVE-2023-6111?

CVE-2023-6111 is classified as a use-after-free vulnerability, specifically falling under CWE-416. This type of vulnerability occurs when a program uses memory after it has been freed, which can lead to a variety of security issues.

The Impact of CVE-2023-6111

The impact of this vulnerability is significant, as it can be exploited by an attacker to elevate their privileges on the affected system. This privilege escalation could potentially grant the attacker unauthorized access to sensitive information or the ability to perform malicious actions.

Technical Details of CVE-2023-6111

The vulnerability was identified in the Linux kernel's netfilter: nf_tables component. The vulnerable function

nft_trans_gc_catchall

fails to remove the catchall set element from the catchall_list when the argument sync is true, allowing for the element to be freed multiple times. The recommended course of action is to upgrade past commit

93995bf4af2c5a99e2a87f0cd5ce547d31eb7630

.

Vulnerability Description

The use-after-free vulnerability in the Linux kernel's nf_tables component enables attackers to trigger local privilege escalation by leveraging the flaw in the catchall set element manipulation.

Affected Systems and Versions

The vulnerability affects Linux Kernel version 6.6, specifically versions less than 6.7. It is crucial for users running these versions to take immediate action to mitigate the risk associated with CVE-2023-6111.

Exploitation Mechanism

Attackers can exploit this vulnerability in the Linux kernel to free a catchall set element multiple times, thereby manipulating the system and gaining elevated privileges.

Mitigation and Prevention

Given the severity of CVE-2023-6111, it is essential to implement immediate steps to protect affected systems and establish long-term security practices to prevent similar vulnerabilities in the future.

Immediate Steps to Take

Update the Linux kernel to a version beyond commit

93995bf4af2c5a99e2a87f0cd5ce547d31eb7630

.
Monitor for any unusual or suspicious activities on the system that may indicate exploitation attempts.
Implement least privilege principles to limit the impact of potential privilege escalation attacks.

Long-Term Security Practices

Regularly update and patch the Linux kernel and related components to address known vulnerabilities promptly.
Conduct regular security assessments and audits to identify and remediate potential weaknesses in the system.
Educate users and administrators on best security practices, including safe browsing habits and system configuration guidelines.

Patching and Updates

Refer to the provided URLs for relevant patches and updates related to CVE-2023-6111. Stay informed about security advisories from reputable sources to stay ahead of emerging threats and vulnerabilities.