CVE-2021-37350
📋 TL;DR
CVE-2021-37350 is a critical SQL injection vulnerability in Nagios XI's Bulk Modifications Tool that allows attackers to execute arbitrary SQL commands. This affects Nagios XI administrators and users with access to the vulnerable component. Successful exploitation could lead to complete compromise of the Nagios XI database and underlying system.
💻 Affected Systems
- Nagios XI
📦 What is this software?
Nagios Xi by Nagios
⚠️ Risk & Real-World Impact
Worst Case
Full database compromise leading to data theft, privilege escalation, and complete system takeover via SQL injection to RCE chain.
Likely Case
Database information disclosure, modification of monitoring configurations, and potential lateral movement within the network.
If Mitigated
Limited impact with proper input validation and database permissions, potentially only allowing data viewing.
🎯 Exploit Status
SQL injection is well-understood and weaponized exploits are common. Requires authenticated access to the vulnerable component.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.8.5 and later
Vendor Advisory: https://www.nagios.com/downloads/nagios-xi/change-log/
Restart Required: Yes
Instructions:
1. Backup current Nagios XI configuration and database. 2. Download Nagios XI 5.8.5 or later from the official Nagios website. 3. Follow the upgrade instructions in the Nagios XI documentation. 4. Restart Nagios XI services after upgrade completion.
🔧 Temporary Workarounds
Disable Bulk Modifications Tool
linuxTemporarily disable access to the vulnerable Bulk Modifications Tool component
# Remove or restrict access to the Bulk Modifications Tool interface
# Modify Apache/Nginx configuration to block access to relevant URLs
Implement WAF Rules
allDeploy web application firewall rules to detect and block SQL injection attempts
# Example ModSecurity rule: SecRule ARGS "@detectSQLi" "id:1001,phase:2,deny"
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Nagios XI from critical systems
- Apply principle of least privilege to database accounts used by Nagios XI
🔍 How to Verify
Check if Vulnerable:
Check Nagios XI version via Admin > System Config > About or run: grep 'nagios_version' /usr/local/nagiosxi/var/xiversionCheck Version:
grep 'nagios_version' /usr/local/nagiosxi/var/xiversionVerify Fix Applied:
Verify version is 5.8.5 or higher and test Bulk Modifications Tool functionality with SQL injection test payloads📡 Detection & Monitoring
Log Indicators:
- Unusual SQL queries in database logs
- Multiple failed authentication attempts followed by Bulk Modifications Tool access
- Unexpected database schema modifications
Network Indicators:
- SQL syntax in HTTP POST parameters to Nagios XI
- Unusual database connection patterns from Nagios XI host
SIEM Query:
source="nagios_access.log" AND (uri="/nagiosxi/admin/bulkmodifications.php" OR uri="/nagiosxi/includes/components/bulkmodifications/") AND (method="POST" OR params CONTAINS "SELECT" OR params CONTAINS "UNION")