CVE-2023-47107
📋 TL;DR
CVE-2023-47107 is a host header injection vulnerability in PILOS that allows attackers to manipulate password reset URLs to point to malicious servers, potentially capturing reset tokens. This affects PILOS deployments with local user accounts and password reset functionality enabled. Attackers could hijack password reset processes to compromise user accounts.
💻 Affected Systems
- PILOS (open source front-end for BigBlueButton)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers capture password reset tokens and take over administrator accounts, gaining full control of the PILOS/BigBlueButton deployment and potentially accessing sensitive meeting data.
Likely Case
Attackers capture password reset tokens for regular users, compromising individual accounts and accessing their meeting history and personal information.
If Mitigated
With proper network segmentation and monitoring, unauthorized password reset attempts are detected and blocked before token capture occurs.
🎯 Exploit Status
Exploitation requires the attacker to trick users into initiating password resets while controlling the host header, but no authentication is needed to trigger the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.3.0
Vendor Advisory: https://github.com/THM-Health/PILOS/security/advisories/GHSA-mc6f-fj9h-5735
Restart Required: Yes
Instructions:
1. Backup current PILOS configuration and data. 2. Update PILOS to version 2.3.0 or later using your deployment method (Docker, manual install, etc.). 3. Restart PILOS services. 4. Verify the update was successful.
🔧 Temporary Workarounds
Disable password reset functionality
allTemporarily disable the password reset feature for local accounts until patching is possible.
Modify PILOS configuration to disable password reset functionality (specific command depends on deployment method)
Configure reverse proxy to validate host headers
linuxConfigure your reverse proxy (nginx, Apache, etc.) to validate and sanitize host headers before they reach PILOS.
# Example nginx configuration to validate host header
if ($host !~ ^(yourdomain\.com|localhost)$) {
return 444;
}
🧯 If You Can't Patch
- Disable password reset functionality for local user accounts
- Implement network-level controls to block or monitor suspicious host header manipulation attempts
🔍 How to Verify
Check if Vulnerable:
Check PILOS version: if running version <2.3.0 with password reset enabled for local accounts, system is vulnerable.Check Version:
Check PILOS web interface admin panel or deployment configuration for version informationVerify Fix Applied:
Verify PILOS version is 2.3.0 or later and test password reset functionality to ensure URLs use configured domain, not request host header.📡 Detection & Monitoring
Log Indicators:
- Unusual host header values in password reset requests
- Multiple password reset attempts from same IP with varying host headers
Network Indicators:
- HTTP requests to password reset endpoint with manipulated host headers
- Outbound connections to unexpected domains following password reset links
SIEM Query:
source="pilos-logs" AND (uri_path="/password/reset" OR uri_path="/password/email") AND http_host!="expected-domain.com"