Project Spring4Shell (CVE-2022-22965 ) Blocker

Firewall Server Handler -

This project is a proof-of-concept (POC) firewall server designed to detect and block attacks exploiting the CVE-2022-22965 vulnerability, commonly known as Spring4Shell. The server inspects incoming HTTP requests and blocks any that match known malicious patterns associated with this vulnerability.

Overview

The Firewall Server Handler is a simple Python-based HTTP server, built using the http.server library. It monitors incoming HTTP POST requests, looking for specific headers and payload patterns associated with the Spring4Shell vulnerability. If a request matches these patterns, it is blocked, and the server responds with a 403 Forbidden status.

Requirements

• Python 3.x

Setup and Usage

1. Clone the Repository

   git clone https://github.com/BlackBird63030/Block-Spring4Shell
   cd Block-Spring4Shell

2. Run the Server

   python frs.py

   By default, the server will run on localhost at port 8000.

3. Test the Firewall Rule

   • To test, you can send use the tnt.py script that simulates the attack by doig 5 connections.

Blocking Rules

This POC uses two main rules to detect and block CVE-2022-22965 exploit attempts:

1. Rule 1: Blocking Payload Pattern

   • Detects requests containing the payload pattern class.module.classLoader.resources.context.parent.pipeline.first, which is used in Spring4Shell exploits to inject malicious Java code.

2. Rule 2: Blocking Suspicious Headers

   • Blocks requests with specific headers characteristic of Spring4Shell attack payloads:
     • suffix: %>//
     • C1: Runtime
     • C2: <%
     • DNT: 1
     • Content-Type: application/x-www-form-urlencoded

If either rule matches, the server responds with a 403 Forbidden status and returns a JSON message: {"error": "Forbidden Access"}

If no conditions are met, the server responds with 200 OK and: {"message": "Request received"}

Code Structure

• ServerHandler: The main class handling HTTP requests.
  • block_request(): Sends a 403 response when a request is blocked.
  • rule_1(): Checks the payload for patterns associated with CVE-2022-22965.
  • rule_2(): Checks for specific headers known to be part of Spring4Shell exploits.
  • do_GET() and do_POST(): Process incoming GET and POST requests, applying the firewall rules.

Example

To test the firewall, use the tnt.py script. It gonna send 5 POST requests to the firewall script

python tnt.py

The server will respond with: {"error": "Forbidden Access"}

Purpose

This POC is intended for educational and testing purposes to demonstrate a basic firewall rule that blocks specific attack vectors targeting the Spring4Shell vulnerability. It is not a substitute for a comprehensive firewall solution in production environments.

License

MIT License