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A10 · Mishandling of Exceptional Conditi · Medium

Missing Role Parameter

A10 · ≈ 30 min · 0 solves

200POINTS
MISSIONDiscover the weakness independently

Explore the application as a real target: map the exposed functionality, inspect requests and responses, build a working exploit, and recover the rotating flag. If you get stuck, the verified official solution is available below as an optional spoiler.

Rules of engagement

Stay inside the generated lab URL. Use only the synthetic accounts and data in this instance. The main SecOne4all site and external systems are out of scope.

Challenge brief

FLAG REQUIREMENTS

What counts as a valid solve

Goal

Omitting a role field selects an unexpectedly privileged default.

Required interaction

POST /create.

Completion proof

trigger the exceptional path and demonstrate its unsafe fallback or partial state; the successful workflow returns the current rotating flag.

Session rule

Work only inside your generated lab URL and submit the flag within 30 minutes.

VERIFIED WALKTHROUGH

Official solution

Contains the complete exploitation path. Open it only when you want the spoiler.

Reveal official solutionStep-by-step · verified against the live lab

Official solution · A10 · Missing Role Parameter

Objective

Omitting a role field selects an unexpectedly privileged default.

Steps

  1. Start the isolated lab and establish the normal response or state.
  2. Prepare the smallest input that triggers the timeout, parser, arithmetic, retry, or cleanup edge case.
  3. Trigger and exploit the exceptional path: POST empty JSON {} to /create, omitting role so the privileged default is selected.
  4. Confirm the unsafe fallback or partial state returns the rotating flag.
  5. Submit the flag before stopping the lab.

Expected proof

A successful response for missing-parameter-privileged-default returns the instance-specific rotating flag. The flag is valid only for the current player and running instance.

Safety boundary

Use only the generated lab URL. No request to the main site, another user, or an external service is part of this solution.