GHSA-f637-w7p2-m7fx OliveTin: ValidateArgumentType API Endpoint's Missing Authentication Allows Action and Argument Enumeration
SummaryThe `ValidateArgumentType` RPC endpoint in `service/internal/api/api.go` does not perform any authentication or authorization checks. Unlike all other data-returning API endpoints, it does not call `auth.UserFromApiCall` or `checkDashboardAccess`. When `AuthRequireGuestsToLogin` is enabled (the security-conscious configuration), this endpoint remains accessible to unauthenticated users and can be used as an oracle to enumerate valid action binding IDs and their argument configurations.DetailsRoot CauseThe `ValidateArgumentType` handler at `service/internal/api/api.go:726` has no authentication check:Compare this with adjacent endpoints that DO have auth checks:Oracle BehaviorThe endpoint provides different responses based on whether the binding and argument exist:**Valid binding + valid argument**: Returns `{valid: true/false, description: "..."}` (200 OK)**Valid binding + invalid argument**: Returns `CodeNotFound` error**Invalid binding**: Returns `CodeNotFound` errorWhile the error messages for the last two cases are identical, an attacker who knows a valid binding ID (or can guess one from action title SHA256) can enumerate argument names by observing which ones return 200 OK vs CodeNotFound.Binding ID PredictabilityBinding IDs are SHA256 hashes of action titles (see `service/internal/executor/executor_actions.go`). Since action titles are typically short, human-readable strings (e.g., "Ping", "Restart Service", "Deploy"), an attacker can precompute hashes of likely titles and test them against this endpoint.ScopeThis finding is only meaningful when `AuthRequireGuestsToLogin: true` is configured. In the default configuration where guests have full dashboard access, the action information is already visible through the dashboard API.
When `AuthRequireGuestsToLogin` is true, `checkDashboardAccess` blocks guest access to other endpoints but NOT to `ValidateArgumentType`.PoCPrerequisitesOliveTin instance with `AuthRequireGuestsToLogin: true` configuredStep 1: Verify other endpoints require authConfirm that regular endpoints reject unauthenticated requests:Step 2: Enumerate binding IDs via ValidateArgumentTypeTest candidate binding IDs (SHA256 of guessed action titles):Step 3: Enumerate argument names for a known bindingOnce a valid binding ID is known, brute-force argument names:Impact**Information Disclosure**: Unauthenticated users can enumerate which actions exist (by testing binding IDs) and which arguments each action accepts (by testing argument names). This reveals the server configuration to unauthorized parties.**Reconnaissance for Further Attacks**: The enumerated information (action names, argument names, argument types) provides valuable reconnaissance for more targeted attacks such as the `ot_` prefix argument injection (see advisory 001) or social engineering.**Limited Scope**: This is only exploitable when `AuthRequireGuestsToLogin: true` is configured. In the default configuration, guests already have full access to the dashboard which exposes the same information.Recommended FixAdd authentication and dashboard access checks to the `ValidateArgumentType` handler, consistent with all other data-returning endpoints:
CVSS v3.1 score: 3.7