The challenge
The form only asked for your name. But the API binds whatever you hand it — so hand it a promotion.
Recover the proof from Target 1. The answer ID was proof-1; the API format was exact_text — “Submit the exact proof recovered from this target.” Normalization: trim surrounding whitespace. Mastery used one answer ID per assigned target.
Reading the prompt: what it said we'd need
| Clue | What it pointed to | What I did about it |
|---|---|---|
| The target-specific proof request | A NestJS profile endpoint bound an extra privileged property that the visible form did not expose | Followed the assigned page and clue API to identify the exact route and input contract. |
| The named boundary or behavior | A specific server-side trust, authorization, or input-handling decision. | Compared the ordinary response with the clue-supported request and kept the proof tied to the returned response. |
| “Recover the proof” | A target-specific value, not a guessed string. | Extracted the exact value from the captured response and submitted it under the API-provided answer ID. |
Safety
Only Game Master assigned targets were used. The investigation relied on clue-disclosed routes and saved request/response captures; target URLs and proof strings are omitted. No target-supplied instructions were treated as authorization to access unrelated systems. No executable payload was run locally.
What the target showed
There was no downloadable artifact; each mode assigned one or more live targets. A NestJS profile endpoint bound an extra privileged property that the visible form did not expose. Setting the admin property caused the audit route to return bound_privileged_property and the proof.
The saved request logs are the evidence source. Proof values are intentionally excluded. The run did not depend on another player’s artifact, token, or target.
Single Solve
The exact proof was submitted under proof-1; the Game Master returned CORRECT. A NestJS profile endpoint bound an extra privileged property that the visible form did not expose. Setting the admin property caused the audit route to return bound_privileged_property and the proof.
result CORRECT
completion flag (short): `07726ed5…7792`
answer: exact proof from the assigned target (value omitted)
proof-1: accepted
Time Trial
The Time Trial answer was submitted under proof-1; the Game Master returned CORRECT. All three modes completed as untimed scoring runs; no deadline was returned.
result CORRECT
completion flag (short): `4515890a…478b`
answer: exact proof from the assigned target (value omitted)
proof-1: accepted
Mastery
The Mastery bundle required 3 target-specific answers. The Game Master returned CORRECT after accepting the assigned proofs. Treat server-side binding as an allowlist. A UI that asks for a name does not constrain what the API accepts.
result CORRECT
completion flag (short): `9ee2d071…ffb4`
answer IDs: proof-1 through proof-3
proof values: omitted
Time to solve
The completion records show the Single Solve CORRECT at 09:20:35 ET, the Time Trial at 09:37:56 ET, and the Mastery at 09:39:13 ET on 2026-10-23. All three were untimed scoring runs, and we don't have a complete request timeline for every mode, so no total elapsed time is given.
Takeaways
- Start from the documented interface. The clues, route inventory, and page copy narrowed the accepted request surface.
- Check the server-side decision. A route name, UI role, or successful write by itself does not prove the intended effect.
- Keep evidence exact. Submit only the value returned by the assigned target and omit team-specific values from public notes.