CVE-2021-38156 in Nagios XI
Summary
by MITRE • 09/15/2021
In Nagios XI before 5.8.6, XSS exists in the dashboard page (/dashboards/#) when administrative users attempt to edit a dashboard.
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Analysis
by VulDB Data Team • 09/19/2021
The vulnerability CVE-2021-38156 represents a cross-site scripting flaw discovered in Nagios XI version 5.8.5 and earlier, specifically affecting the dashboard editing functionality. This security weakness resides within the web interface of Nagios XI, a widely used network monitoring and management platform that organizations rely on to maintain visibility into their IT infrastructure. The vulnerability manifests when administrative users attempt to edit dashboard components through the dashboard page located at /dashboards/#, creating a potential attack vector that could compromise the security posture of monitored environments.
The technical implementation of this XSS vulnerability stems from insufficient input validation and output encoding within the dashboard editing functionality. When administrative users interact with the dashboard modification interface, the application fails to properly sanitize user-supplied data before rendering it back to the browser. This allows attackers to inject malicious scripts that execute within the context of the victim's browser session. The flaw specifically affects the administrative user accounts with dashboard editing privileges, making it particularly concerning for organizations that maintain multiple administrative users with elevated access rights.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a range of malicious activities within the targeted environment. An attacker who successfully exploits this vulnerability could potentially steal administrative session cookies, allowing unauthorized access to the Nagios XI management interface. Additionally, the attacker could manipulate dashboard content to display misleading information, potentially causing operational confusion during critical incidents. The vulnerability also creates opportunities for privilege escalation attacks where attackers might attempt to gain additional system access through the compromised administrative session.
Organizations utilizing Nagios XI should implement immediate mitigations to address this vulnerability, beginning with upgrading to version 5.8.6 or later where the XSS protection has been implemented. Network administrators should also consider implementing additional defensive measures such as web application firewalls that can detect and block malicious script injection attempts. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications, and it maps to ATT&CK technique T1059.007 for scripting and T1566.001 for spearphishing with a malicious attachment. Security teams should conduct thorough testing of the patched version to ensure proper implementation and monitor for any signs of exploitation attempts. Regular security assessments of the Nagios XI installation, including input validation reviews and penetration testing, should be performed to identify and remediate similar vulnerabilities that may exist in other parts of the application.