CVE-2019-25421
📋 TL;DR
CVE-2019-25421 is a cross-site scripting vulnerability in Comodo Dome Firewall that allows attackers to inject malicious JavaScript through the policyfw endpoint. This enables execution of arbitrary code in administrator browsers or persistent script storage, potentially compromising firewall management. Organizations using Comodo Dome Firewall 2.7.0 are affected.
💻 Affected Systems
- Comodo Dome Firewall
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of firewall administration, credential theft, installation of backdoors, and lateral movement into protected networks.
Likely Case
Session hijacking of administrator accounts, data exfiltration from firewall management interface, and potential privilege escalation.
If Mitigated
Limited to client-side script execution with no server compromise if proper input validation and output encoding are implemented.
🎯 Exploit Status
Exploit requires POST requests with JavaScript payloads in mac, target, and remark parameters; public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.8.0 or later
Vendor Advisory: https://cdome.comodo.com/firewall/
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Download latest version from Comodo portal. 3. Install update following vendor documentation. 4. Restart firewall services. 5. Verify functionality.
🔧 Temporary Workarounds
Input Validation Filter
allImplement web application firewall rules to filter JavaScript in POST parameters
WAF specific - configure rules to block <script> tags and JavaScript patterns in mac, target, remark parameters
Access Restriction
linuxRestrict access to firewall management interface to trusted IP addresses only
iptables -A INPUT -p tcp --dport [admin-port] -s [trusted-ip] -j ACCEPT
iptables -A INPUT -p tcp --dport [admin-port] -j DROP
🧯 If You Can't Patch
- Implement strict Content Security Policy headers to prevent script execution
- Enable HTTPOnly and Secure flags on all session cookies
🔍 How to Verify
Check if Vulnerable:
Test by submitting POST requests to policyfw endpoint with benign JavaScript payloads in mac, target, or remark parameters and check if executed in response.Check Version:
ssh admin@firewall-ip 'show version' or check web interface About pageVerify Fix Applied:
After patching, repeat vulnerability test; payloads should be properly encoded and not execute.📡 Detection & Monitoring
Log Indicators:
- POST requests to /policyfw with JavaScript patterns in parameters
- Unusual administrator login patterns or session activity
Network Indicators:
- HTTP traffic to firewall admin interface containing <script> tags or JavaScript functions in POST data
SIEM Query:
source="firewall-logs" AND (url="*policyfw*" AND (data="*<script>*" OR data="*javascript:*" OR data="*onload=*"))