CVE-2011-10040
📋 TL;DR
This cross-site scripting (XSS) vulnerability in Nagios XI allows attackers to inject malicious scripts into status and report pages. When exploited, these scripts execute in victims' browsers, potentially stealing session cookies or performing actions as authenticated users. Organizations running Nagios XI versions before 2011R1.9 are affected.
💻 Affected Systems
- Nagios XI
📦 What is this software?
Nagios Xi by Nagios
Nagios Xi by Nagios
Nagios Xi by Nagios
Nagios Xi by Nagios
Nagios Xi by Nagios
Nagios Xi by Nagios
Nagios Xi by Nagios
Nagios Xi by Nagios
Nagios Xi by Nagios
Nagios Xi by Nagios
⚠️ Risk & Real-World Impact
Worst Case
Attacker steals administrator session cookies, gains full administrative access to Nagios XI, modifies monitoring configurations, or uses the system as a pivot point to attack other internal systems.
Likely Case
Attacker steals user session cookies to gain unauthorized access to monitoring data, creates fake alerts, or modifies dashboard views to hide actual system issues.
If Mitigated
Script execution is blocked by browser security features or Content Security Policy, limiting impact to minor UI manipulation.
🎯 Exploit Status
Exploitation requires user interaction (clicking malicious links) and some knowledge of Nagios XI's interface structure.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2011R1.9 or later
Vendor Advisory: https://www.nagios.com/changelog/nagios-xi/
Restart Required: No
Instructions:
1. Backup current Nagios XI configuration. 2. Download latest Nagios XI version from official website. 3. Follow upgrade instructions in Nagios XI documentation. 4. Verify upgrade completed successfully.
🔧 Temporary Workarounds
Implement Content Security Policy
allAdd CSP headers to restrict script execution sources and prevent inline script execution
Add to web server config: Content-Security-Policy: default-src 'self'; script-src 'self'
Input Validation Filter
allAdd custom input validation for link parameters in status and report pages
Implement server-side validation for all user-supplied URL parameters before processing
🧯 If You Can't Patch
- Restrict Nagios XI access to trusted internal networks only using firewall rules
- Implement web application firewall (WAF) rules to block XSS payloads in URL parameters
🔍 How to Verify
Check if Vulnerable:
Check Nagios XI version via Admin > System Config > About page or run: grep 'nagiosxi_version' /usr/local/nagiosxi/var/xiversionCheck Version:
grep 'nagiosxi_version' /usr/local/nagiosxi/var/xiversionVerify Fix Applied:
Verify version is 2011R1.9 or later and test status/report pages with XSS payloads in URL parameters📡 Detection & Monitoring
Log Indicators:
- Unusual long URLs with script tags in Nagios access logs
- Multiple failed login attempts following suspicious URL accesses
Network Indicators:
- HTTP requests containing <script> tags or javascript: protocol in URL parameters to Nagios XI endpoints
SIEM Query:
source="nagios_access.log" AND (url="*<script>*" OR url="*javascript:*")