CVE-2023-6735: Privilege Escalation Vulnerability in Checkmk’s mk_tsm Agent Plugin

Overview

CVE-2023-6735 is a high-severity vulnerability identified in the ‘mk_tsm’ agent plugin of Checkmk, a comprehensive IT monitoring system. This flaw allows local users to escalate their privileges on affected systems. The vulnerability affects Checkmk versions prior to 2.2.0p18, 2.1.0p38, and 2.0.0p39. The issue arises from improper input validation and the unsafe use of the ‘eval’ function within the plugin, leading to potential exploitation. ​GitHub+5CVE+5Checkmk+5Checkmk+5Debian Security Tracker+5AttackerKB+5Checkmk

Vulnerability Summary

• CVE ID: CVE-2023-6735​

• Severity: High (CVSS Score: 8.8)​Checkmk

• Attack Vector: Local​CVE Database

• Privileges Required: Low​Checkmk+2CVE+2Debian Security Tracker+2

• User Interaction: None​GitHub+5Checkmk+5CVE+5

• Impact: Confidentiality High, Integrity High, Availability High​Debian Security Tracker+3CVE Database+3Ubuntu+3

Affected Products

How the Exploit Works

The vulnerability stems from the ‘mk_tsm’ agent plugin’s use of the ‘eval’ function without proper input validation. An attacker can craft a malicious command that appears in the output of the ‘ps’ command. Due to insufficient quoting and the unsafe use of ‘eval’, this can lead to the execution of arbitrary commands with elevated privileges. ​GitHub+5Checkmk+5CVE Database+5

Potential Risks

Exploitation of this vulnerability allows a local attacker to execute arbitrary code with root privileges. This can lead to complete system compromise, unauthorized access to sensitive data, and potential lateral movement within the network.​

Mitigation Recommendations

• Update Software: Upgrade Checkmk to version 2.2.0p18, 2.1.0p38, or 2.0.0p39, where this vulnerability has been addressed.​GitHub+5CVE+5AttackerKB+5

• Disable Vulnerable Plugin: If immediate updating is not feasible, disable the ‘mk_tsm’ agent plugin to mitigate the risk.​Checkmk

• Review and Monitor: Regularly review system logs and monitor for unusual activities, especially related to the ‘mk_tsm’ plugin.​Checkmk

Conclusion

CVE-2023-6735 is a critical vulnerability that poses significant risks to systems running affected versions of Checkmk. Prompt action is required to update the software or disable the vulnerable plugin to prevent potential exploitation. Regular monitoring and adherence to best security practices are essential to safeguard systems against such vulnerabilities.