CVE-2021-36366 in Nagios XI
Summary
by MITRE • 09/28/2021
Nagios XI before 5.8.5 incorrectly allows manage_services.sh wildcards.
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Analysis
by VulDB Data Team • 10/03/2021
Nagios XI is a comprehensive monitoring solution that provides network and system monitoring capabilities for enterprise environments. The vulnerability described in CVE-2021-36366 affects versions prior to 5.8.5 and relates to improper handling of wildcards within the manage_services.sh script. This script is designed to manage service configurations and operations within the Nagios XI environment, serving as a critical component for system administrators to maintain monitoring infrastructure. The flaw manifests in how the system processes wildcard characters when executing service management commands, creating potential security risks that could be exploited by unauthorized users.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the manage_services.sh script. When users submit commands containing wildcard characters such as asterisks or question marks, the system fails to properly restrict or escape these characters before processing them. This allows malicious actors to craft specially formatted inputs that can bypass intended access controls and execute unintended operations. The vulnerability specifically impacts the service management functionality, potentially enabling attackers to manipulate service configurations, access restricted resources, or perform unauthorized administrative actions. The flaw represents a classic example of improper input handling that can lead to privilege escalation or arbitrary command execution.
The operational impact of this vulnerability extends beyond simple access control bypasses and can significantly compromise the integrity and availability of monitoring systems. Attackers could exploit this weakness to modify critical service configurations, disable monitoring alerts, or gain elevated privileges within the Nagios XI environment. Organizations relying on Nagios XI for critical infrastructure monitoring face potential operational disruptions if attackers successfully exploit this vulnerability, as it could lead to undetected system failures or unauthorized modifications to monitoring parameters. The vulnerability particularly affects environments where Nagios XI is used for enterprise-level monitoring, where the integrity of service configurations directly impacts business continuity and security operations.
Organizations should immediately upgrade to Nagios XI version 5.8.5 or later to address this vulnerability, as this release includes proper input validation and sanitization for wildcard characters in the manage_services.sh script. System administrators should also implement additional monitoring and access controls around the affected script, ensuring that only authorized personnel can execute service management operations. The mitigation strategy should include reviewing existing access controls and permissions for the manage_services.sh script, implementing network segmentation to limit access to monitoring infrastructure, and conducting regular security assessments to identify similar input validation issues. This vulnerability aligns with CWE-20, which addresses improper input validation, and could potentially map to ATT&CK technique T1059 for command and scripting interpreter usage, particularly when attackers leverage wildcard expansion for privilege escalation or lateral movement within monitored environments.