The challenge
The exact Game Master prompt was not saved, so it isn't quoted here.
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 | The preferences flow allowed a cross-site change of the signed-in user’s notification destination | 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. The preferences flow allowed a cross-site change of the signed-in user’s notification destination. The saved log shows the preference change and changed_across_sites: true, followed by proof in the preferences API.
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. The saved log shows the cross-site preference change and changed_across_sites: true, followed by the proof in the preferences API.
result CORRECT
completion flag (short): `c4e1e8ef…0918`
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.
result CORRECT
completion flag (short): `fd001fc4…c357`
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. A signed-in session and a form token did not make the state change safe; what matters is whether the server binds the operation to a same-origin anti-CSRF check.
result CORRECT
completion flag (short): `65405cc1…8c0e`
answer IDs: proof-1 through proof-3
proof values: omitted
Time to solve
The saved completion records show the Single Solve CORRECT at 09:16:00 ET, the Time Trial at 09:23:57 ET, and Mastery at 09:28:34 ET, all as untimed runs with no deadline. Start times were not preserved 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.