CVE-2023-23549 : Exploit Details and Defense Strategies

This CVE-2023-23549 was published by Checkmk on November 15, 2023. It involves the improper input validation in versions <2.2.0p15, <2.1.0p37, and <=2.0.0p39 of the Checkmk software, allowing privileged attackers to cause a partial denial of service of the UI by utilizing hostnames that are too long.

Understanding CVE-2023-23549

This section will delve into what CVE-2023-23549 entails, its impact, technical details, and mitigation strategies.

What is CVE-2023-23549?

CVE-2023-23549 is a vulnerability found in the Checkmk software versions <2.2.0p15, <2.1.0p37, and <=2.0.0p39 due to improper input validation. This flaw enables attackers with elevated privileges to disrupt the user interface by employing excessively long hostnames.

The Impact of CVE-2023-23549

The impact of this vulnerability, categorized under CAPEC-153 (Input Data Manipulation), is classified as low severity with a CVSS v3.1 base score of 2.7. It allows attackers to execute partial denial of service attacks on the user interface.

Technical Details of CVE-2023-23549

In this section, we will explore the vulnerability description, affected systems and versions, as well as the exploitation mechanism.

Vulnerability Description

The vulnerability in Checkmk <2.2.0p15, <2.1.0p37, and <=2.0.0p39 stems from improper input validation, which can be exploited by malicious actors with heightened privileges to disrupt the UI by utilizing overly long hostnames.

Affected Systems and Versions

The affected versions include:

Checkmk 2.2.0 versions less than p15
Checkmk 2.1.0 versions less than p37
Checkmk 2.0.0 versions less than or equal to p39

Exploitation Mechanism

Attackers with high privileges can exploit this vulnerability by submitting excessively long hostnames, leading to a partial denial of service of the user interface.

Mitigation and Prevention

To mitigate the risks associated with CVE-2023-23549, users are advised to take immediate steps, follow long-term security practices, and apply necessary patches and updates.

Immediate Steps to Take

Upgrade to the latest version of Checkmk to ensure the vulnerability is patched.
Monitor user input for excessively long hostnames to prevent exploitation.

Long-Term Security Practices

Implement regular security audits and vulnerability scans.
Educate staff on secure coding practices to avoid input validation issues.

Patching and Updates

Checkmk has released patches to address this vulnerability. Users are urged to apply the relevant updates promptly to safeguard their systems from exploitation.