CVE-2019-25400
📋 TL;DR
This vulnerability allows attackers to execute reflected cross-site scripting (XSS) attacks against IPFire firewall administrators. By injecting malicious JavaScript into multiple parameters of the fwhosts.cgi script, attackers can execute arbitrary code in authenticated users' browsers. This affects IPFire administrators who access the web interface.
💻 Affected Systems
- IPFire
📦 What is this software?
Ipfire by Ipfire
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator session cookies, perform actions as the administrator (including firewall rule changes), or redirect to malicious sites.
Likely Case
Session hijacking leading to unauthorized access to the firewall administration interface.
If Mitigated
Limited impact if administrators use separate accounts with least privilege and browsers have XSS protection enabled.
🎯 Exploit Status
Exploitation requires the attacker to trick an authenticated user into clicking a malicious link. Public exploit code is available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: IPFire 2.21 Core Update 128 or later
Vendor Advisory: https://www.ipfire.org/news
Restart Required: No
Instructions:
1. Log into IPFire web interface as admin. 2. Navigate to System > Updates. 3. Apply all available updates. 4. Verify version is 2.21 Core Update 128 or newer.
🔧 Temporary Workarounds
Input Validation via ModSecurity
linuxImplement ModSecurity rules to block XSS payloads in the affected parameters
# Add to ModSecurity rules: SecRule ARGS "@detectXSS" "id:1001,phase:2,deny,status:403,msg:'XSS Attack Detected'"
Restrict Web Interface Access
allLimit access to the IPFire web interface to trusted IP addresses only
# In IPFire firewall rules, restrict port 444 (HTTPS) to admin networks only
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to prevent script execution from untrusted sources
- Use browser extensions that provide XSS protection for administrators
🔍 How to Verify
Check if Vulnerable:
Check if version is 2.21 Core Update 127 via web interface System > Status or command: cat /etc/ipfire-releaseCheck Version:
cat /etc/ipfire-releaseVerify Fix Applied:
Verify version is 2.21 Core Update 128 or newer and test XSS payloads in fwhosts.cgi parameters return sanitized output📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cgi-bin/fwhosts.cgi with script tags or JavaScript in parameters
- Multiple failed login attempts followed by XSS payload requests
Network Indicators:
- HTTP requests containing <script>, javascript:, or other XSS payloads in URL parameters
SIEM Query:
source="ipfire_web.log" AND uri="/cgi-bin/fwhosts.cgi" AND (param="HOSTNAME" OR param="IP" OR param="SUBNET") AND (value="*<script>*" OR value="*javascript:*")