zwesty
Write-ups / Day 25 / Web
Day 25 · Sun, Oct 25 · Web

Resolver Revolt

Prey slaughtered

GraphQL schema discovery, resolver-level authorization

STTMClaude Homebase Both

Flags are shortened to their first 8 and last 4 characters because they're unique per team.

Challenge ID
web-exploitation-day-18-resolver-revolt (+ /time_trial, /mastery)
Curriculum day
18
Solved
2026-10-25; Single Solve, Time Trial, and Mastery each recorded CORRECT.
Player
Zwesty (solo), with the Homebase agent (GPT-6 Luna), which made the successful target requests; Claude Code did not.
Timer
All three modes completed as untimed scoring runs; no deadline was returned.

The challenge

Discover the schema and reach a resolver whose field-level control is incomplete. Vary the protocol surface without changing the underlying authorization discipline.

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 GraphQL introspection exposed caseIndex and case(id) 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. GraphQL introspection exposed caseIndex and case(id). The index listed an executive reference as reference only; querying its note field still returned 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. GraphQL introspection exposed caseIndex and case(id). The index listed an executive reference as reference only; querying its note field still returned the proof.

result CORRECT
completion flag (short): `ea9625ca…4b2e`
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): `345d2f24…0cad`
answer: exact proof from the assigned target (value omitted)
proof-1: accepted

Mastery

The Mastery bundle required 4 target-specific answers. The Game Master returned CORRECT after accepting the assigned proofs. A hidden or reference-only object is not protected if the resolver for a sensitive field skips the access check. Use the disclosed schema and indexed reference.

result CORRECT
completion flag (short): `4165ded2…d016`
answer IDs: proof-1 through proof-4
proof values: omitted

Time to solve

The completion records show the Single Solve CORRECT at 09:15:46 ET, the Time Trial at 09:16:50 ET, and the Mastery at 09:19:09 ET on 2026-10-25. 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.