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Web3 Sandbox

Broken Access Control

Find an accidentally deployed code sandbox for writing smart contracts on the fly.

Difficulty​

⭐☆☆☆☆☆ 1-Star Challenge (Easy)

Description​

An accidentally exposed endpoint (/web3-sandbox) grants access to a smart contract code sandbox. The endpoint requires no authentication or authorization, making this a textbook example of Broken Access Control.

Broken Access Control occurs when users are able to access functions or data they are not authorized to interact with. This typically results from missing or misconfigured access control mechanisms.

Hint​

Find an accidentally deployed code sandbox.

  • It is just as easy as finding the Score Board.

Approach​

  1. The lab environment was started, and the Juice Shop application was accessed via browser:
    http://127.0.0.1:3000

  2. Using the browser DevTools (F12), the source code (index.html, main.js, etc.) was examined for potential hidden routes, including keywords such as:

    • /sandbox
    • /web
    • /editor
    • /contracts
    • /access
    • ...

    DevTools

  3. Accessing the URL: http://127.0.0.1:3000/# + /web3-sandbox opened a publicly accessible code sandbox interface.

  4. The challenge automatically marked as solved upon visiting the page.

Evidence (Screenshot)​

URL: http://127.0.0.1:3000/#/web3-sandbox
Status Code: 200 OK
Access: No authentication or special permissions required

Sandbox Screenshot