CVE-2018-13458 in Nagios
Summary
by MITRE
qh_core in Nagios Core 4.4.1 and earlier is prone to a NULL pointer dereference vulnerability, which allows attackers to cause a local denial-of-service condition by sending a crafted payload to the listening UNIX socket.
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Analysis
by VulDB Data Team • 11/29/2024
The vulnerability identified as CVE-2018-13458 resides within the qh_core component of Nagios Core versions 4.4.1 and earlier, representing a critical NULL pointer dereference flaw that enables local denial-of-service conditions. This issue specifically affects the UNIX socket listening functionality where the application fails to properly validate incoming payloads before processing them. The vulnerability stems from inadequate input sanitization and memory management within the core processing module that handles queued requests. Attackers can exploit this weakness by crafting malicious payloads designed to trigger a NULL pointer dereference when the system attempts to access an uninitialized memory location. The flaw manifests when the qh_core component receives malformed data through the UNIX socket interface, causing the application to crash and terminate unexpectedly.
The technical implementation of this vulnerability aligns with CWE-476 which specifically addresses NULL pointer dereference conditions in software applications. The flaw operates at the system level where the qh_core module fails to perform proper null checks on pointer variables before dereferencing them during payload processing. This creates a condition where legitimate system operations become disrupted due to the application's inability to handle unexpected input gracefully. The vulnerability exists in the core processing logic where the application assumes certain memory locations contain valid data without proper validation. When the crafted payload is sent through the UNIX socket, it triggers an execution path that leads to the dereference of a NULL pointer, causing the process to terminate abruptly.
From an operational perspective, this vulnerability presents significant risk to systems relying on Nagios Core for monitoring and alerting functions. The local denial-of-service condition can disrupt critical infrastructure monitoring capabilities, potentially leading to extended periods without system visibility during which security incidents may go undetected. The impact extends beyond simple service interruption as it can affect the reliability of automated alerting systems and monitoring dashboards that depend on continuous Nagios operation. Organizations using affected Nagios versions may experience cascading failures where the monitoring system itself becomes unavailable, creating a dangerous situation where the very tool designed to detect system failures is compromised. The vulnerability's local nature means that exploitation requires access to the system hosting the Nagios service, but this access level is often sufficient for attackers who have already compromised system credentials or have physical access to the infrastructure.
Mitigation strategies for CVE-2018-13458 should prioritize immediate patching of Nagios Core installations to versions 4.4.2 or later where the NULL pointer dereference has been addressed. System administrators should implement network segmentation and access controls to limit exposure of the UNIX socket interface to only trusted entities. The ATT&CK framework's T1068 technique for "Exploitation for Privilege Escalation" is relevant here as this vulnerability could be leveraged by attackers to maintain persistent access through service disruption. Additional defensive measures include implementing monitoring for unusual process termination patterns and establishing automated alerting for service availability. Organizations should also consider implementing input validation layers and runtime protections that can detect and block malformed payloads before they reach the vulnerable qh_core component. Regular vulnerability assessments and penetration testing should be conducted to identify similar memory corruption issues in other system components. The remediation process must include thorough testing of patched versions in non-production environments to ensure that the fix does not introduce regressions in system functionality while maintaining the integrity of monitoring operations.