Courses / HTTP Header Manipulation: IP Spoofing

Manipulating Headers

Last Edit: 10-05-2024

HTTP header spoofing involves manipulating the headers of HTTP requests to achieve specific objectives, such as impersonating different IP addresses. As a penetration tester, IP spoofing can help test network security, uncover vulnerabilities, and assess security measures like Web Application Firewalls (WAFs). 

Understanding IP Spoofing in HTTP Headers

IP spoofing in HTTP headers typically focuses on altering the source IP address or related information to mislead web servers or bypass security controls.

Too many servers still trust this information and will take it into account, allowing the attacker to use it at his advantage.

The most common headers involved in IP spoofing is X-Forwarded-For but Client-IP and X-Real-IP are commonly used too.

The "X-Forwarded-For" Header

The X-Forwarded-For (XFF) header is used by proxy servers to identify the original client IP address when requests pass through multiple proxies. Spoofing this header can simulate requests from different IP addresses, enabling penetration testers to test server responses to spoofed IPs.

Other Headers for IP Spoofing

  • Client-IP: Similar to XFF, used to indicate the original client IP.
  • X-Real-IP: Typically used to pass the client IP through reverse proxies.

Question Answer the question below to validate the course and earn easy points:

What is the main header to manipulate to mislead misconfigured service or servers?