credential-verification

Validates recovered API keys and tokens using a three-state differential testing method.

7|4|Updated Jun 22, 2026
One-click install
npx skills add https://github.com/dbx0/skills --skill credential-verification-dbx0
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: credential-verification
Source: https://github.com/dbx0/skills/tree/main/skills/methodology/triage/credential-verification
Command: npx skills add https://github.com/dbx0/skills --skill credential-verification-dbx0

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? Recovered credentials from bundles, configs, or leaks are often reported as live findings without proof, leading to rejected reports, false positives on restricted cloud keys, or accidental abuse of privileged actions outside program scope. ## Core Features & Use Cases - Three-State Verification Method: Compare responses from no credential, a bogus credential of the right shape, and the recovered credential to prove an endpoint actually validates the secret. - Gateway and mTLS Detection: Identify when a live credential is non-exploitable externally because it sits behind DataPower, F5, or Imperva gateways requiring mutual TLS. - Cloud Key Restriction Analysis: Distinguish referrer/IP restrictions from service-level blocks (e.g., API_KEY_SERVICE_BLOCKED) on Google, Firebase, and AWS keys to avoid overstated "unrestricted key" claims. - Use Case: After extracting a Google API key from a mobile app bundle, test it against StaticMap, Geocoding, and signUp endpoints to determine exactly which services are callable before writing the finding. ## Quick Start Verify whether this recovered API key is live using the three-state method and tell me exactly which restrictions apply before I report it.

Frequently Asked Questions about credential-verification

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I verify if a leaked API key is still valid?

Use the three-state method: send no credential, a bogus credential of the correct format, and the recovered key against the same endpoint. Three distinguishable responses prove the key is live without exercising any privileged action.

How to test a Google API key for restrictions?

Test the key against its intended API from a server-side context with no referrer header. A response like API_KEY_SERVICE_BLOCKED means service-level restriction applies even without referrer limits, so only claim unrestricted if the real target API succeeds.

Why does a valid credential return the same error as no credential?

The endpoint is likely behind a gateway such as IBM DataPower, F5, or Imperva that authenticates the client application via mutual TLS. The credential never reaches the validating layer, making it a hardcoded-secret hygiene issue rather than an exploitable bypass.

Are Firebase API keys a security finding?

Firebase web and Android keys are non-secret by design; the finding depends on backend configuration. Test Realtime Database, Firestore, Storage, and signUp endpoints unauthenticated to determine whether rules are enforced or data is openly readable.

When should I stop testing a verified credential?

Stop after proving liveness with the three-state method. Forging signatures, writing data, or altering production config requires explicit program authorization; document what the credential could do and let the program approve the next phase.