CVE-2019-9167 in Nagios XI
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Nagios XI before 5.5.11 allows attackers to inject arbitrary web script or HTML via the xiwindow parameter.
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Analysis
by VulDB Data Team • 08/17/2023
The vulnerability identified as CVE-2019-9167 represents a critical cross-site scripting flaw in Nagios XI versions prior to 5.5.11, exposing organizations to significant web application security risks. This vulnerability specifically affects the xiwindow parameter handling within the Nagios XI monitoring platform, which is widely used for network and system monitoring across enterprise environments. The issue stems from inadequate input validation and output sanitization mechanisms that fail to properly escape or filter user-supplied data before rendering it in web responses. Attackers can exploit this weakness by crafting malicious payloads that leverage the xiwindow parameter to inject arbitrary JavaScript code or HTML content into the application's response, potentially compromising user sessions and system integrity.
The technical exploitation of this XSS vulnerability follows established patterns that align with CWE-79, which categorizes cross-site scripting as a code injection flaw occurring when untrusted data is embedded into web pages without proper sanitization. The vulnerability exists because Nagios XI fails to implement proper context-aware output encoding when processing the xiwindow parameter, allowing attackers to inject malicious scripts that execute in the context of other users' browsers. This particular attack vector demonstrates the classic characteristics of reflected XSS, where the malicious payload is embedded in a URL or HTTP request and delivered to the victim through social engineering or direct link sharing. The vulnerability affects the web interface components of Nagios XI that handle window management and parameter processing, creating a persistent attack surface that could be leveraged for session hijacking, credential theft, or data exfiltration.
The operational impact of CVE-2019-9167 extends beyond simple script injection, as it enables attackers to potentially escalate privileges within the monitoring environment and gain unauthorized access to sensitive system information. Organizations relying on Nagios XI for critical infrastructure monitoring face elevated risks of unauthorized system access, as successful exploitation could allow attackers to execute malicious code in the context of authenticated users. The vulnerability's presence in monitoring platforms like Nagios XI creates a particularly concerning threat landscape since these systems often contain sensitive operational data, system configurations, and access credentials. Attackers could leverage this vulnerability to establish persistent access points, conduct reconnaissance activities, or launch further attacks against the broader network infrastructure. The potential for privilege escalation through XSS attacks increases the severity of the vulnerability, as compromised monitoring interfaces often provide administrative access to critical system components.
Mitigation strategies for CVE-2019-9167 should prioritize immediate patching of Nagios XI installations to version 5.5.11 or later, which contains the necessary input validation and output sanitization fixes. Organizations should implement comprehensive web application firewall rules that monitor for suspicious parameter patterns and block known malicious payloads targeting the xiwindow parameter. The remediation process should include thorough input validation that enforces strict parameter constraints and implements proper output encoding mechanisms to prevent script execution in web contexts. Security teams should also consider implementing additional monitoring and logging controls to detect potential exploitation attempts, while conducting regular security assessments of web applications to identify similar vulnerabilities. The vulnerability aligns with ATT&CK technique T1059.007 for scripting and T1566 for social engineering, emphasizing the need for both technical and user awareness-based defenses. Organizations should also review their incident response procedures to ensure rapid detection and remediation of XSS vulnerabilities, as these attacks can remain undetected for extended periods, allowing for prolonged unauthorized access to critical monitoring systems.