CVE-2023-25824 : Exploit Details and Defense Strategies

This CVE record involves the mod_gnutls container, highlighting an Infinite Loop on request read timeout vulnerability.

Understanding CVE-2023-25824

This vulnerability (CVE-2023-25824) affects the mod_gnutls container, specifically versions from 0.9.0 to 0.12.0. It allows attackers to exploit an infinite loop on request read timeout, potentially leading to denial of service attacks.

What is CVE-2023-25824?

Mod_gnutls is a TLS module designed for Apache HTTPD and is based on GnuTLS. The identified versions of 0.9.0 to 0.12.0 have a flaw where they do not properly handle blocking read operations on TLS connections when a transport hits timeouts. Instead of failing the operation, the module enters an endless loop, consuming CPU resources. In addition to the CPU consumption, if trace level logging is enabled, it generates excessive log output, consuming disk space. The issue has been resolved in commit d7eec4e598158ab6a98bf505354e84352f9715ec, and users are advised to update to version 0.12.1. For users unable to update immediately, applying the errno fix outlined in the security advisory is recommended.

The Impact of CVE-2023-25824

The impact of this vulnerability is rated as high, with a CVSS v3.1 base score of 7.5. The attack complexity is low, requiring no special privileges, but it can have a significant availability impact, making it crucial to address promptly.

Technical Details of CVE-2023-25824

This section delves deeper into the technical aspects of CVE-2023-25824.

Vulnerability Description

The vulnerability in mod_gnutls versions 0.9.0 to 0.12.0 results in an infinite loop when facing timeouts on TLS connections, leading to excessive CPU usage and potential denial of service attacks.

Affected Systems and Versions

The affected system is mod_gnutls by airtower-luna, specifically versions between 0.9.0 and 0.12.0.

Exploitation Mechanism

Attackers can exploit this vulnerability by triggering a request read timeout, causing the mod_gnutls module to enter an infinite loop, thereby consuming CPU resources and potentially disrupting services.

Mitigation and Prevention

To safeguard against CVE-2023-25824, consider the following mitigation strategies and preventive measures.

Immediate Steps to Take

Update to version 0.12.1 of mod_gnutls to address the vulnerability and prevent exploitation.
If immediate updating is not feasible, apply the errno fix detailed in the security advisory to mitigate the risk temporarily.

Long-Term Security Practices

Regularly monitor and apply security updates for all software components to stay protected against emerging vulnerabilities.
Implement network security measures to detect and prevent abnormal traffic patterns that could indicate a denial of service attack.

Patching and Updates

Stay informed about security advisories and updates released for mod_gnutls to ensure timely patching of vulnerabilities and secure your systems against potential threats.