CVE-2019-25396
📋 TL;DR
CVE-2019-25396 is a reflected cross-site scripting (XSS) vulnerability in IPFire's updatexlrator.cgi script that allows attackers to inject malicious JavaScript via POST parameters. When exploited, attackers can execute arbitrary scripts in users' browsers, potentially stealing session cookies or performing actions on behalf of authenticated users. This affects IPFire administrators and users who access the vulnerable web interface.
💻 Affected Systems
- IPFire
📦 What is this software?
Ipfire by Ipfire
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator session cookies, gain full control of the IPFire firewall, reconfigure network rules, intercept traffic, or use the firewall as a pivot point into internal networks.
Likely Case
Attackers would steal session cookies to impersonate administrators, potentially modifying firewall rules or accessing sensitive configuration data.
If Mitigated
With proper input validation and output encoding, the malicious scripts would be rendered harmless as text rather than executed code.
🎯 Exploit Status
Exploit requires the attacker to trick a user into clicking a malicious link or visiting a crafted page. Public exploit code exists on Exploit-DB.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: IPFire 2.21 Core Update 128 or later
Vendor Advisory: https://www.ipfire.org
Restart Required: No
Instructions:
1. Log into IPFire web interface as administrator. 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 Filter
linuxAdd input validation to filter script tags and JavaScript from MAX_DISK_USAGE and MAX_DOWNLOAD_RATE parameters
Modify /var/ipfire/cgi-bin/updatexlrator.cgi to sanitize user input
Web Application Firewall
allDeploy a WAF with XSS protection rules to block malicious requests
🧯 If You Can't Patch
- Restrict access to the IPFire web interface to trusted internal networks only using firewall rules
- Implement Content Security Policy (CSP) headers to restrict script execution sources
🔍 How to Verify
Check if Vulnerable:
Test by sending a POST request to /cgi-bin/updatexlrator.cgi with script payload in MAX_DISK_USAGE parameter and checking if it executesCheck Version:
cat /var/ipfire/general-functions.pl | grep 'our $VERSION'Verify Fix Applied:
After patching, repeat the test and verify script payloads are properly encoded and not executed📡 Detection & Monitoring
Log Indicators:
- Web server logs showing POST requests to updatexlrator.cgi with script tags or JavaScript in parameters
- Unusual parameter values containing <script>, javascript:, or eval() patterns
Network Indicators:
- HTTP requests to /cgi-bin/updatexlrator.cgi with suspicious parameter values
- Outbound connections from IPFire to unexpected external domains after XSS execution
SIEM Query:
source="ipfire_web_logs" AND uri="/cgi-bin/updatexlrator.cgi" AND (param_value="*<script>*" OR param_value="*javascript:*")