CVE-2018-13441 in Nagios
Summary
by MITRE
qh_help in Nagios Core version 4.4.1 and earlier is prone to a NULL pointer dereference vulnerability, which allows attacker 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 • 11/30/2024
The vulnerability identified as CVE-2018-13441 affects Nagios Core versions 4.4.1 and earlier, specifically within the qh_help component that handles help requests. This issue represents a critical NULL pointer dereference flaw that can be exploited to trigger a local denial-of-service condition. The vulnerability manifests when the system receives a specially crafted payload through the listening UNIX socket interface, which is commonly used for communication between Nagios components and external monitoring tools.
The technical implementation of this vulnerability stems from improper input validation within the qh_help function, which fails to adequately check for NULL pointer references before attempting to dereference memory addresses. When an attacker sends malformed data through the UNIX socket, the function processes the input without proper null checks, leading to a segmentation fault that crashes the Nagios process. This behavior aligns with CWE-476 which specifically addresses NULL pointer dereference vulnerabilities, where a pointer that is expected to contain a valid memory address instead contains NULL, causing the application to crash when attempting to access that memory location.
The operational impact of this vulnerability extends beyond simple service disruption as it can be exploited locally by users who have access to the UNIX socket interface. Attackers can leverage this weakness to repeatedly crash the Nagios monitoring service, potentially leading to extended periods of system unavailability and loss of critical monitoring capabilities. This denial-of-service condition directly impacts the availability aspect of the CIA triad, as it prevents legitimate users from accessing monitoring services. The vulnerability is particularly concerning in enterprise environments where Nagios serves as a critical infrastructure monitoring tool, as any disruption can cascade into broader operational failures.
Security practitioners should implement immediate mitigations including upgrading to Nagios Core version 4.4.2 or later where this vulnerability has been patched. Additionally, system administrators should restrict access to the UNIX socket interface to trusted users only and implement proper input validation mechanisms. The ATT&CK framework categorizes this vulnerability under T1499 which covers network disruption techniques, and T1566 which covers credential access through exploitation of software vulnerabilities. Organizations should also consider implementing monitoring for unusual process termination patterns and ensure regular security updates are applied to all monitoring infrastructure components to prevent exploitation of similar vulnerabilities in other parts of the system.