Server-Side Request Smuggling (SSRS)


Summary: Server-Side Request Smuggling (SSRS) is a severe web security vulnerability that enables an attacker to manipulate the way a front-end server and a back-end server process and interpret HTTP requests. By exploiting this vulnerability, an attacker can smuggle or manipulate HTTP requests, potentially bypassing security mechanisms and gaining unauthorized access to sensitive data or performing actions on behalf of other users.

Severity: High

Request Method:

Complexity: Medium

Origin: Remote/External

Steps to Reproduce:

1. Identify the target system that utilizes a front-end and back-end server architecture vulnerable to SSRS.
2. Craft a specially manipulated HTTP request that takes advantage of inconsistencies or misinterpretations between the front-end and back-end servers.
3. Send the manipulated request, combining different techniques such as request splitting, parameter pollution, or chunked encoding abuse.
4. Observe and analyze the behavior of the front-end and back-end servers to determine if the smuggling attack was successful.

Impact: Exploiting SSRS can lead to various consequences, including unauthorized access to sensitive data, session hijacking, privilege escalation, bypassing security controls, or even remote code execution.

Affected IP Address: https://www.example.com/

Port: 443

Recommendations:

To mitigate Server-Side Request Smuggling vulnerabilities, the following measures are recommended:
1. Regularly update and patch all involved servers and components.
2. Implement secure coding practices to handle HTTP requests and ensure proper request parsing and interpretation.
3. Utilize a Web Application Firewall (WAF) or security solutions that can detect and mitigate SSRS attacks.
4. Perform thorough security testing, including vulnerability assessments and penetration testing, to identify and address any existing vulnerabilities.

References:

1. OWASP - Server-Side Request Forgery: https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
2. Imperva - Server-Side Request Forgery: https://www.imperva.com/learn/application-security/server-side-request-forgery-ssrf/

Proof of Concept:

Please refer to the attached screenshot or video for a visual demonstration of a Server-Side Request Smuggling attack.