CVE-2020-15902 in Nagios XI
Summary
by MITRE
Graph Explorer in Nagios XI before 5.7.2 allows XSS via the link url option.
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Analysis
by VulDB Data Team • 07/23/2020
The vulnerability identified as CVE-2020-15902 represents a cross-site scripting flaw within the Graph Explorer component of Nagios XI versions prior to 5.7.2. This security weakness specifically manifests when processing the link url option, creating an avenue for malicious actors to inject and execute arbitrary script code within the context of a victim's browser session. The Graph Explorer functionality is designed to provide visualization capabilities for monitoring data, making it a critical component within the Nagios XI ecosystem that requires robust security controls. The flaw exists due to insufficient input validation and sanitization of user-supplied data within the link url parameter, allowing attackers to craft malicious payloads that can be executed when the affected interface renders the crafted URL.
The technical implementation of this vulnerability stems from the application's failure to properly escape or filter special characters in the link url field before rendering it within the web interface. When a user navigates to a page containing the vulnerable Graph Explorer component and interacts with a crafted link url, the malicious script code becomes embedded in the HTML output and executes in the context of the authenticated user's browser. This behavior aligns with CWE-79 which categorizes cross-site scripting vulnerabilities as weaknesses that occur when an application incorporates untrusted data into web pages without proper validation or escaping. The vulnerability is particularly concerning because Nagios XI is commonly deployed in enterprise environments where it serves as a critical monitoring solution, making it an attractive target for attackers seeking to escalate privileges or gain unauthorized access to monitoring infrastructure.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, data exfiltration, and privilege escalation within the monitoring environment. An attacker could potentially craft a malicious link url that redirects users to phishing sites, steals authentication cookies, or executes commands on behalf of the authenticated user. The vulnerability is particularly dangerous in environments where Nagios XI is used for critical infrastructure monitoring, as successful exploitation could provide attackers with insights into network topology, service availability, and system configurations. According to ATT&CK framework, this vulnerability maps to T1059.007 for scripting and T1566.001 for spearphishing with attachments, as attackers could leverage this flaw to deliver malicious payloads through crafted monitoring links. The affected environment typically includes system administrators and security personnel who regularly interact with the Graph Explorer interface, making them potential targets for social engineering attacks that exploit this vulnerability.
Organizations should implement immediate mitigations including upgrading to Nagios XI version 5.7.2 or later, which contains the necessary patches to address the input validation issues. Additionally, network administrators should consider implementing web application firewalls to detect and block suspicious script payloads, while also reviewing access controls to limit exposure of the vulnerable interface. The remediation process should include thorough testing of the patched version to ensure compatibility with existing monitoring configurations and alerting mechanisms. Security teams should also conduct regular vulnerability assessments of their monitoring infrastructure to identify similar input validation weaknesses that may exist in other components of the Nagios XI platform. Implementation of proper input sanitization and output encoding practices should be enforced across all user-facing interfaces to prevent similar vulnerabilities from emerging in the future, aligning with security best practices outlined in OWASP Top Ten and NIST cybersecurity frameworks.