CVE-2024-13998 is a vulnerability classified under CWE-497, indicating exposure of sensitive system information to unauthorized control spheres within Nagios XI, a widely used IT infrastructure monitoring platform. The flaw exists in versions prior to 2024R1.1.3 and allows authenticated users with limited privileges to access sensitive user account data, including API keys and hashed passwords, which should be restricted. This unauthorized disclosure arises due to insufficient access control enforcement in certain application components, enabling privilege escalation in terms of data visibility. The exposure of API keys can lead to abuse of API privileges, allowing attackers to perform unauthorized actions within the monitoring environment. Similarly, access to hashed passwords increases the risk of offline cracking attempts, potentially leading to full account compromise. The vulnerability does not require user interaction and can be exploited remotely over the network by users with low privileges, making it relatively easy to exploit in environments where multiple users have access to Nagios XI. This issue follows CVE-2024-13995, which addressed a similar problem but with an incomplete fix, indicating a persistent underlying access control weakness. No public exploits have been reported yet, but the potential impact on confidentiality and integrity is significant. The CVSS v4.0 score of 6.0 reflects a medium severity, considering the ease of exploitation and the sensitive nature of the exposed data. The vulnerability affects the confidentiality of sensitive credentials and the integrity of user accounts but does not directly impact availability. Nagios XI is commonly deployed in enterprise environments, including many European organizations, for monitoring critical IT infrastructure, making this vulnerability relevant for those relying on this product for operational continuity and security monitoring.

For European organizations, the exposure of API keys and hashed passwords in Nagios XI can lead to unauthorized access to monitoring systems, manipulation of monitoring data, and potential disruption of IT operations. Compromise of API keys could allow attackers to automate malicious actions, such as disabling alerts or injecting false data, undermining the reliability of monitoring and incident response. Offline cracking of password hashes could lead to broader account compromise, especially if users reuse credentials across systems. This risk is heightened in sectors with stringent regulatory requirements for data protection and operational security, such as finance, healthcare, energy, and government. The breach of monitoring credentials could also serve as a foothold for lateral movement within networks, increasing the risk of more extensive intrusions. Given the critical role of Nagios XI in infrastructure monitoring, exploitation could degrade situational awareness and delay detection of other security incidents. The medium severity rating suggests a moderate but tangible risk, particularly in environments with multiple users and insufficient privilege segregation.

European organizations should immediately upgrade Nagios XI installations to version 2024R1.1.3 or later, where the vulnerability is addressed. In addition to patching, organizations should conduct a thorough audit of user roles and permissions within Nagios XI to ensure the principle of least privilege is enforced, limiting access to sensitive information only to necessary personnel. Implement strict API key management policies, including regular rotation and revocation of unused keys. Monitor API usage logs for unusual or unauthorized activity that could indicate abuse. Employ network segmentation and access controls to restrict Nagios XI access to trusted users and systems only. Consider integrating multi-factor authentication (MFA) for Nagios XI user accounts to reduce the risk of credential compromise. Finally, review and enhance monitoring and alerting around Nagios XI to detect potential exploitation attempts promptly. Organizations should also verify that previous fixes (e.g., for CVE-2024-13995) have been fully applied and effective.