exploiting-excessive-data-exposure-in-api

# Exploiting Excessive Data Exposure in API ## When to Use - Testing APIs where the frontend displays a subset of data but the API response includes additional fields - Assessing mobile application APIs where responses are designed for multiple client types and may contain excess data - Identifying PII leakage in API responses that include email addresses, phone numbers, SSNs, or payment data not shown in the UI - Testing GraphQL APIs where clients can request arbitrary fields including sensitive attributes - Evaluating APIs after microservice refactoring where internal service-to-service data leaks into public endpoints **Do not use** without written authorization. Data exposure testing involves capturing and analyzing potentially sensitive personal data. ## Prerequisites - Written authorization specifying target API endpoints and scope - Burp Suite Professional or mitmproxy configured as intercepting proxy - Two test accounts at different privilege levels (regular user and admin) - Browser developer tools or mobile proxy setup for traffic capture - Python 3.10+ with `requests` and `json` libraries - API documentation (OpenAPI spec) for comparison against actual responses > **Legal Notice:** This skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws. ## Workflow ### Step 1: Response Schema Discovery Compare documented A...