CVE-2020-36865 in Nagios
Summary
by MITRE • 10/31/2025
Nagios XI versions prior to 5.7.2 are vulnerable to cross-site scripting (XSS) via the BPI (Business Process Intelligence) component’s Config Management and Edit Config page. Insufficient validation or escaping of user-supplied input may allow an attacker to inject and execute arbitrary script in the context of a victim's browser.
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Analysis
by VulDB Data Team • 10/31/2025
Nagios XI versions prior to 5.7.2 contain a critical cross-site scripting vulnerability within its Business Process Intelligence component that exposes the system to persistent script injection attacks. This vulnerability specifically affects the Config Management and Edit Config pages of the BPI module, creating an attack surface where malicious actors can exploit insufficient input validation mechanisms. The flaw allows remote attackers to inject malicious JavaScript code that executes in the context of authenticated users' browsers, potentially leading to unauthorized access, data exfiltration, or further compromise of the monitoring infrastructure. The vulnerability represents a significant risk to organizations relying on Nagios XI for critical infrastructure monitoring, as it undermines the integrity of the user interface and can be leveraged to escalate privileges or steal session tokens.
The technical implementation of this vulnerability stems from inadequate sanitization of user-supplied input within the BPI configuration management interfaces. When administrators or authorized users navigate to the Config Management or Edit Config pages, the application fails to properly validate or escape potentially malicious input parameters. This weakness enables attackers to craft specially crafted payloads that bypass security controls, allowing arbitrary JavaScript execution within the victim's browser context. The vulnerability is classified as a classic XSS flaw under CWE-79, which specifically addresses improper neutralization of input during web page generation. The attack vector requires minimal privileges since the injection occurs in administrative interfaces, making it particularly dangerous for environments where multiple users have access to the monitoring system. The persistent nature of the vulnerability means that malicious scripts can remain active until the affected pages are reloaded or the session expires.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform session hijacking, modify configuration settings, or gain unauthorized access to sensitive monitoring data. An attacker who successfully exploits this vulnerability could potentially manipulate business process intelligence reports, alter alert configurations, or even redirect users to malicious websites. The affected environment becomes vulnerable to credential theft, as session cookies and authentication tokens may be accessible to the malicious scripts. Organizations using Nagios XI for critical infrastructure monitoring face significant risk since the compromised system could provide attackers with visibility into network operations and security events. The vulnerability can be exploited through various attack vectors including phishing emails, compromised user accounts, or by leveraging other initial access points to reach the affected administrative interfaces. This represents a substantial risk to operational security and can lead to extended periods of unauthorized access without detection.
Organizations should immediately upgrade to Nagios XI version 5.7.2 or later to address this vulnerability, as the patch includes proper input validation and output escaping mechanisms for the affected BPI components. System administrators should also implement additional security controls such as web application firewalls to monitor and filter suspicious requests to the affected pages. Regular security assessments should be conducted to identify other potential XSS vulnerabilities within the monitoring infrastructure, particularly in administrative interfaces where user input is processed. Network segmentation and privilege separation can help limit the impact if exploitation occurs, while comprehensive logging of administrative activities can aid in detecting unauthorized access attempts. The vulnerability highlights the importance of maintaining current security patches and implementing robust input validation practices across all web applications. Organizations should also consider implementing additional security measures such as content security policies and regular security training for administrators to reduce the risk of successful exploitation through social engineering attacks. The incident underscores the critical need for continuous security monitoring and rapid patch deployment to protect against emerging threats in operational technology environments.