How to remediate – HAProxy Statistics Page Detection

1. Introduction

The HAProxy Statistics Page Detection vulnerability refers to an exposed web-based statistics page on systems running HAProxy load balancers. This page can reveal sensitive information about your internal network infrastructure, including the version of HAProxy in use. This could allow attackers to gather intelligence for further attacks or exploit known vulnerabilities in older versions. Confidentiality is most at risk.

2. Technical Explanation

The vulnerability occurs because the statistics page is often left unprotected and accessible from the internet or untrusted networks. An attacker can directly access this page via a web browser to view configuration details, internal server names, and potentially other sensitive data. There is no CVE associated with this specific exposure; it’s a misconfiguration issue. An attacker could use this information to map your network topology and identify potential targets for exploitation.

• Root cause: The HAProxy statistics page has default access enabled without authentication or restriction.
• Exploit mechanism: An attacker sends an HTTP request to the statistics page URL, typically on port 80 or 443.
• Scope: All systems running HAProxy with a publicly accessible statistics page are affected.

3. Detection and Assessment

You can confirm whether your system is vulnerable by checking if the statistics page is accessible from outside your trusted network. A thorough method involves reviewing the HAProxy configuration file.

• Quick checks: Use a web browser to access http://your_haproxy_ip:80/stats or https://your_haproxy_ip:443/stats (replace with your actual IP address and port). If you see the statistics page, it’s likely exposed.
• Scanning: Nessus plugin ID 16279 can detect an open HAProxy stats page. This is an example only.
• Logs and evidence: Check web server logs for requests to /stats from untrusted IP addresses.

curl -I http://your_haproxy_ip:80/stats

4. Solution / Remediation Steps

Protect the statistics page by password protecting it or restricting access to trusted networks.

4.1 Preparation

• Take a backup of your HAProxy configuration file (haproxy.cfg). Stop the HAProxy service if necessary for changes.
• Ensure you have SSH access to the server and understand basic text editing commands. A roll back plan is to restore the backed-up haproxy.cfg file.
• A change window may be required depending on your environment; approval from a system administrator might be needed.

4.2 Implementation

1. Step 1: Edit the haproxy.cfg file and add an authentication section to protect the stats page.
2. Step 2: Restart the HAProxy service to apply the changes.

4.3 Config or Code Example

Before

listen stats
  bind *:8080
  stats enable
  stats uri /stats
  stats realm Local Stats

After

listen stats
  bind *:8080
  stats enable
  stats uri /stats
  stats realm Local Stats
  stats auth username:password

4.4 Security Practices Relevant to This Vulnerability

• Least privilege: Restrict access to the statistics page to only authorized personnel and networks.
• Secure defaults: Avoid using default configurations that expose sensitive information.

4.5 Automation (Optional)

No automation is provided, as configuration changes are specific to each environment.

5. Verification / Validation

Confirm the fix by attempting to access the statistics page without credentials and verifying you are prompted for authentication. Then test with valid credentials.

• Post-fix check: Access http://your_haproxy_ip:80/stats in a web browser; you should see an authentication prompt.
• Re-test: Repeat the quick check from section 3 and confirm that access is now restricted.
• Smoke test: Ensure legitimate users can still access the statistics page with valid credentials.
• Monitoring: Monitor HAProxy logs for failed login attempts to /stats.

curl -I http://your_haproxy_ip:80/stats

6. Preventive Measures and Monitoring

• Baselines: Update your security baseline or policy to require authentication for all HAProxy statistics pages.
• Pipelines: Implement configuration checks in CI/CD pipelines to ensure the stats page is always protected.
• Asset and patch process: Regularly review HAProxy configurations during asset inventory and patching cycles.

7. Risks, Side Effects, and Roll Back

• Roll back: Restore the backed-up haproxy.cfg file and restart the HAProxy service.

8. References and Resources

• Vendor advisory or bulletin: http://haproxy.1wt.eu/
• NVD or CVE entry: Not applicable, as this is a misconfiguration issue.