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One More Login Challenge

Daily AlpacaHackTopic: MongoDBReleased: Apr 16, 2026

135 solves
Web
Medium

by

tchen

tchen

Login again?! (Note: You don't necessarily have to solve Another Login Challenge first)

Beginner Hint 1: Overview of the Challenge
  • In index.js, a simple login feature is implemented.
  • It appears to use MongoDB to check whether a user with the submitted username and password exists.
  • It does not seem possible to create your own user. Also, a user called admin is registered, but guessing that password would be impossible.
Beginner Hint 2: How to Approach the Challenge
  • As mentioned in the comments, it seems possible to send data in both application/x-www-form-urlencoded and application/json formats. Therefore, if you use JSON, you can send non-string values in username and password.
  • The login form alone might not allow you to send the intended data. For methods of sending data without using a browser, refer to my writeup for I wanna be the Admin.
Beginner Hint 3: When you are really stuck
  • Try searching for MongoDB injection or NoSQL injection.
one-more-login-challenge.tar.gz

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