CVE-2024-13723 in NagVis
Summary
by MITRE • 02/05/2025
The "NagVis" component within Checkmk is vulnerable to remote code execution. An authenticated attacker with administrative level privileges is able to upload a malicious PHP file and modify specific settings to execute the contents of the file as PHP.
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Analysis
by VulDB Data Team • 03/06/2025
The NagVis component within Checkmk presents a critical remote code execution vulnerability that fundamentally compromises system integrity and security posture. This vulnerability specifically targets the administrative interface of Checkmk, where NagVis serves as a visualization tool for network monitoring and management. The flaw exists in how the system handles file uploads and execution permissions, creating a pathway for malicious actors to gain unauthorized code execution capabilities. The vulnerability requires an attacker to possess administrative credentials, which significantly reduces the attack surface but does not eliminate the severity of potential impact. The compromised system becomes vulnerable to full command execution through PHP file manipulation, effectively allowing attackers to assume complete control over the affected infrastructure.
The technical implementation of this vulnerability stems from inadequate input validation and insufficient access controls within the NagVis component's file handling mechanisms. When administrators upload files through the web interface, the system fails to properly validate file extensions, content types, or execution permissions. This allows authenticated users to upload PHP files that can subsequently be executed by the web server. The vulnerability is particularly dangerous because it operates within the legitimate administrative interface, making it difficult to detect through standard network monitoring. The attack vector involves uploading a malicious PHP payload that can execute arbitrary commands on the server, potentially leading to data exfiltration, system compromise, or further lateral movement within the network infrastructure. This flaw aligns with CWE-434, which addresses insecure file upload vulnerabilities, and represents a classic example of insufficient access control mechanisms.
The operational impact of this vulnerability extends far beyond simple code execution, as it enables attackers to completely subvert the security controls that Checkmk is designed to provide. Once an attacker successfully uploads and executes malicious PHP code, they can access all monitored systems, extract sensitive data, modify configuration settings, and potentially establish persistent backdoors. The administrative privileges required for exploitation mean that the vulnerability could be leveraged by insiders or through credential compromise, making detection particularly challenging. Organizations relying on Checkmk for network monitoring and security operations face significant risk of undetected compromise, as the malicious code execution occurs within the legitimate monitoring infrastructure. This creates a false sense of security while simultaneously providing attackers with elevated privileges and access to critical network information. The vulnerability essentially transforms the monitoring system from a security tool into a potential attack vector, undermining the fundamental trust placed in such infrastructure.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements within the Checkmk environment. The primary recommendation involves applying the latest security patches provided by Checkmk, which should address the file upload validation and access control issues. Organizations should implement strict file upload restrictions, including MIME type validation, file extension filtering, and execution permission controls. Network segmentation and principle of least privilege should be enforced to limit the potential impact of successful exploitation. Regular security auditing of administrative interfaces, including monitoring for unusual file upload activities and unauthorized configuration changes, should be implemented. The use of web application firewalls and intrusion detection systems can help detect and prevent exploitation attempts. Additionally, implementing multi-factor authentication for administrative accounts and regular credential rotation significantly reduces the risk of unauthorized access. Organizations should also consider conducting security assessments to identify similar vulnerabilities in other components of their monitoring infrastructure, as this vulnerability demonstrates the importance of proper input validation and access control mechanisms in security-critical applications.