CVE-2021-30185
📋 TL;DR
CVE-2021-30185 is a host header injection vulnerability in CERN Indico that allows attackers to manipulate password reset links. By supplying a malicious Host header, attackers can redirect password reset emails to domains they control, potentially leading to account takeover. This affects all Indico installations before version 2.3.4.
💻 Affected Systems
- CERN Indico
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete account takeover of administrative users leading to full system compromise, data exfiltration, and privilege escalation across the Indico platform.
Likely Case
Targeted account takeover of specific users through crafted password reset links, potentially leading to unauthorized access to sensitive conference materials and user data.
If Mitigated
Limited impact with proper email verification and monitoring, though password reset functionality remains temporarily disabled for affected users.
🎯 Exploit Status
Exploitation requires no authentication and minimal technical skill, making this easily weaponizable in real attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.3.4
Vendor Advisory: https://github.com/indico/indico/releases/tag/v2.3.4
Restart Required: Yes
Instructions:
1. Backup your Indico installation and database. 2. Update to Indico 2.3.4 or later using pip: 'pip install indico>=2.3.4'. 3. Restart the Indico service. 4. Verify the update completed successfully.
🔧 Temporary Workarounds
Disable Password Reset
allTemporarily disable the password reset functionality in Indico configuration
Edit indico.conf and set ENABLE_PASSWORD_RESET = False
Web Server Host Validation
linuxConfigure your web server (nginx/apache) to validate Host headers
For nginx: add 'if ($host !~* ^(yourdomain.com|www.yourdomain.com)$ ) { return 444; }' to server block
🧯 If You Can't Patch
- Implement strict web server configuration to validate and sanitize Host headers
- Enable multi-factor authentication for all user accounts to reduce impact of password reset attacks
🔍 How to Verify
Check if Vulnerable:
Check Indico version: if version is less than 2.3.4, system is vulnerableCheck Version:
python -c "import indico; print(indico.__version__)"Verify Fix Applied:
Verify Indico version is 2.3.4 or higher and test password reset functionality with various Host headers📡 Detection & Monitoring
Log Indicators:
- Unusual Host header values in HTTP logs
- Multiple password reset requests from single IP
- Password reset attempts with non-standard domains
Network Indicators:
- HTTP requests with manipulated Host headers to password reset endpoints
- Unusual outbound connections following password reset requests
SIEM Query:
source="indico_logs" AND (url="*/reset-password" OR url="*/forgot-password") AND host!="*yourdomain.com*"