CVE-2018-8733 in Nagios XI
Summary
by MITRE
Authentication bypass vulnerability in the core config manager in Nagios XI 5.2.x through 5.4.x before 5.4.13 allows an unauthenticated attacker to make configuration changes and leverage an authenticated SQL injection vulnerability.
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Analysis
by VulDB Data Team • 12/20/2024
The vulnerability identified as CVE-2018-8733 represents a critical authentication bypass flaw within Nagios XI's core configuration manager that affects versions 5.2.x through 5.4.x prior to 5.4.13. This vulnerability operates at the intersection of authentication and authorization controls, creating a pathway for unauthenticated attackers to gain unauthorized access to sensitive system configuration functions. The flaw stems from inadequate validation of user credentials within the configuration management interface, allowing malicious actors to bypass standard authentication mechanisms and directly interact with system configuration components. This vulnerability is particularly concerning as it serves as a gateway to more severe exploitation opportunities within the Nagios XI platform.
The technical implementation of this authentication bypass occurs through a flaw in the core configuration manager's access control logic where proper session validation is not enforced for critical configuration endpoints. Attackers can exploit this weakness by crafting specific requests that circumvent the normal authentication flow, effectively granting them access to system configuration interfaces without proper credentials. The vulnerability is classified under CWE-287, which addresses improper authentication issues, and aligns with ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting. The flaw specifically affects the authentication mechanisms that should validate user credentials before granting access to configuration management functions, creating a persistent access vector that remains active until the patch is applied.
The operational impact of CVE-2018-8733 extends far beyond simple unauthorized access, as it enables attackers to modify critical system configurations that govern monitoring and alerting functions. This capability allows adversaries to potentially disable monitoring alerts, modify service checks, alter notification settings, and manipulate system behavior in ways that could go undetected for extended periods. The vulnerability becomes even more dangerous when combined with the authenticated SQL injection vulnerability mentioned in the description, as it provides attackers with a complete attack chain from initial access through data manipulation. Organizations using Nagios XI in production environments face significant risks including potential service disruption, data integrity compromise, and the possibility of attackers using the compromised system as a pivot point for further network infiltration.
Mitigation strategies for CVE-2018-8733 require immediate patch application to Nagios XI versions 5.4.13 and later, as this represents the official fix for the authentication bypass vulnerability. Organizations should also implement network segmentation to limit access to Nagios XI interfaces, particularly restricting administrative access to trusted networks and implementing strict firewall rules that limit exposure of the configuration management endpoints. Additional protective measures include implementing robust monitoring for unusual configuration changes, enabling detailed logging of all configuration management activities, and conducting regular security assessments of the Nagios XI environment. The vulnerability demonstrates the importance of proper access control implementation and highlights the need for continuous security testing of core system components, particularly those handling configuration management functions. Organizations should also consider implementing multi-factor authentication for administrative access and establish strict change management procedures for configuration modifications to detect and prevent unauthorized alterations to system monitoring parameters.