Exploiting Server Version Disclosure

What Is Server Version Disclosure?

Server Version Disclosure occurs when a web server exposes its software name and version number in the Server HTTP response header. This header may also reveal the operating system or other internal components used by the server.

Exposing this information helps attackers identify known vulnerabilities specific to the disclosed versions, making it easier to launch targeted attacks.

How to Detect Server Version Disclosure

Detecting server version disclosure is simple and passive. The Server header is present in most HTTP responses. You can view it using browser developer tools or any HTTP client, such as curl:

$ curl -I example.com

HTTP/1.1 200 OK  
Date: Mon, 17 Mar 2025 10:25:28 GMT  
Server: Apache/2.4.50 (Debian)  
Content-Type: text/html  

In the example above, the server reveals:

• Web server software: Apache
• Version: 2.4.50
• Operating system: Debian

⚠️ Note: The Server header might be absent or obfuscated based on server settings. For reliable detection, use an automated scanner like SmartScanner.

ℹ️ also read: Why you should use passive vulnerability scan on your website

How Attackers Exploit Server Version Disclosure

While the Server header itself isn’t a direct vulnerability, it enables attackers to:

• Identify the exact server version
• Search for related public exploits on platforms like CVE Details or Exploit-DB

Example: If Server: Apache/2.4.50 is exposed, searching reveals CVE-2021-41773, a high-severity RCE vulnerability. Public exploits for it exist, making exploitation trivial.

⚠️ Headers can be faked, but most often they reveal accurate information unless explicitly configured otherwise.

How to Prevent Server Version Disclosure

Most web servers allow you to disable or customize the Server header. Here are guides for popular platforms:

• Hide Apache Server Version
• Hide Nginx Server Version
• Hide Tomcat Server Version

⚠️ Obscuring version info does not fix the underlying vulnerabilities. Always keep your software updated to the latest secure versions.

💡 More about Http headers: Complete HTTP Headers Cheat Sheet

Bonus: ASP.NET Version Disclosure

In ASP.NET environments, the following headers may expose sensitive version info:

• X-AspNet-Version
• X-AspNetMvc-Version

Learn how to disable them here: 👉 Fix ASP.NET Version Disclosure

Was that interesting? Continue reading this: 5 Security Vulnerabilities You Can Fix Right Now