CVE-2021-21407
📋 TL;DR
CVE-2021-21407 is a Cross-Site Request Forgery (CSRF) vulnerability in Combodo iTop that allows attackers to bypass CSRF token validation through a tricky browser procedure. This enables attackers to perform unauthorized actions on behalf of authenticated users. All iTop installations prior to version 2.7.4 are affected.
💻 Affected Systems
- Combodo iTop
📦 What is this software?
Itop by Combodo
⚠️ Risk & Real-World Impact
Worst Case
Attackers could perform administrative actions like creating new privileged accounts, modifying configurations, or deleting critical data, potentially leading to complete system compromise.
Likely Case
Attackers trick authenticated users into performing unintended actions like changing their password, modifying tickets, or altering user permissions.
If Mitigated
With proper CSRF protections and user awareness, impact is limited to specific targeted actions requiring user interaction.
🎯 Exploit Status
Exploitation requires tricking an authenticated user into visiting a malicious page. The advisory describes a specific browser procedure to bypass CSRF tokens.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.7.4 or 3.0.0
Vendor Advisory: https://github.com/Combodo/iTop/security/advisories/GHSA-9wq8-4qm9-3j6f
Restart Required: Yes
Instructions:
1. Backup your iTop installation and database. 2. Download iTop version 2.7.4 or 3.0.0 from the official repository. 3. Follow the iTop upgrade documentation to apply the patch. 4. Restart the web server service.
🔧 Temporary Workarounds
Implement CSRF Protection Headers
allAdd additional CSRF protection headers to web server configuration
# For Apache: Add 'Header set X-Frame-Options DENY' to .htaccess
# For Nginx: Add 'add_header X-Frame-Options DENY;' to server config
Session Timeout Reduction
allReduce session timeout to limit exposure window
# In iTop configuration file, reduce 'session_timeout' parameter
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to detect and block CSRF attempts
- Educate users about phishing risks and implement strict access controls for sensitive operations
🔍 How to Verify
Check if Vulnerable:
Check iTop version in the web interface footer or configuration files. If version is below 2.7.4, the system is vulnerable.Check Version:
grep 'ITOP_VERSION' /path/to/iTop/config-itop.phpVerify Fix Applied:
After patching, verify version shows 2.7.4 or higher in the web interface. Test CSRF protection by attempting to submit forms without valid tokens.📡 Detection & Monitoring
Log Indicators:
- Multiple failed CSRF token validations from same IP
- Unusual administrative actions from non-admin users
- Requests with missing or malformed CSRF tokens
Network Indicators:
- POST requests without Referer headers
- Requests with suspicious Origin headers
- Multiple form submissions from same session in short time
SIEM Query:
source="iTop_logs" AND (message="CSRF token validation failed" OR message="Invalid CSRF token") | stats count by src_ip