Ensure default error and index.html pages do not reference NGINX

MediumLevel 1Manual reviewnginx

Description

Default error pages (e.g., 404, 500) and the default welcome page often contain NGINX branding or signatures. These pages should be removed or replaced with generic or custom-branded pages that do not disclose the underlying server technology. Manual review: the benchmark gives no reliable automated check for this control.

How it is checked

Audit method: Manual review

This recommendation cannot be checked automatically. A scan lists it with these instructions when you pass --include-manual.

1. Verify Config: Check if error_page directives are active: nginx -T 2>/dev/null | grep -i "error_page" 2. Verify Content (Functional Test): Trigger an error (e.g., request a non-existent page) and inspect the body: curl -k https://127.0.0.1/non-existent-page | grep -i "nginx" Evaluation: PASS: The output does not contain "nginx" (or grep returns nothing). FAIL: The HTML body contains "nginx".

How it is fixed

Fix method: Guidance or infrastructure patch

Instead of editing the default files (which may be overwritten by package updates), configure NGINX to use custom error pages. 1. Create Custom Error Pages: Create a directory (e.g., /var/www/html/errors) and place generic HTML files there (e.g., 404.html, 50x.html) without NGINX branding. 2. Configure NGINX: Add the error_page directive to your http or server blocks: error_page 404 /404.html; error_page 500 502 503 504 /50x.html; location = /50x.html { root /var/www/html/errors; internal; }

Properties

Operating systems: Any
Tags: nginxconfiguration
Reference: CIS NGINX Benchmark v3.0.0 - 2.5.2 Ensure default error and index.html pages do not reference NGINX