CSRF Token

Overview

A CSRF Token is an unpredictable value bound to a user session or request context that a server validates to help prevent cross-site request forgery. The control exists to prevent APIs and applications from allowing unauthorized data access, privileged functions, unsafe state changes, or execution through defective design or implementation. It is not an access token and should not be treated as proof of user identity or broad authorization. It should be interpreted alongside Access Token because the concepts can affect the same decision without representing the same control, event, or risk.

The workflow starts with explicit trust boundaries, identities, objects, fields, functions, states, and allowed transitions. Server-side controls validate every request, use restrictive schemas, calculate authoritative values, and reject operations that violate authorization, sequence, rate, content, or business rules. In this context, safe implementation requires cryptographic unpredictability, server-side validation, correct session binding, protection from leakage, rotation where appropriate, compatible cookie controls, rejection of missing or invalid values, and testing of state-changing endpoints.

It should connect the term to Business Logic Vulnerability where that relationship changes access, transaction treatment, investigation, communication, or recovery.

Testing should include positive and negative authorization cases, multiple roles and tenants, malformed and replayed requests, concurrency, version changes, nested data, recovery paths, and production-like configurations. Logs should connect principal, request, resource, decision, error, and resulting state without recording secrets.

Useful measures include endpoint coverage, failed authorization tests, vulnerable versions, time to remediate, abuse attempts, error and rejection rates, recurring defect classes, and differences between specification and deployed behavior.

The relationship with Authentication Failures should be documented where it affects residual risk or control ownership.