API Excessive Data Exposure Scanner
Detects APIs returning more data than necessary.
What is API Excessive Data Exposure?
API Excessive Data Exposure occurs when APIs return more data than clients need, relying on the client to filter sensitive information. APIs might return complete user objects including password hashes, internal IDs, private fields, or other users' data that the client isn't supposed to display.
Why is This Important?
Returning excessive data exposes sensitive information to attackers who examine raw API responses. Even if the UI hides data, it's visible in browser tools, proxies, or API exploration. This enables PII exposure, competitive intelligence leaks, and assists in further attacks.
How It Works
1. API Discovery
Automatically discovers API endpoints, methods, parameters, and authentication mechanisms from documentation or traffic.
2. Security Testing
Tests for OWASP API Top 10 vulnerabilities including broken authentication, excessive data exposure, and injection flaws.
3. Compliance Validation
Validates API security against industry standards with detailed findings and remediation guidance.
Key Capabilities
Complete API security coverage aligned with OWASP API Security Top 10 and industry best practices.
- Automatic API endpoint discovery
- Authentication and authorization testing
- Rate limiting and resource exhaustion checks
- Data exposure and sensitive info detection
- API versioning and deprecation analysis
Frequently Asked Questions
What data exposure issues should I look for?
Look for: password hashes or tokens in responses, internal IDs or database keys, other users' data in list endpoints, admin-only fields in user responses, PII beyond what's displayed, and debug/logging information.
Why do APIs expose excessive data?
Causes: generic serialization of database objects, same endpoint serving different clients with different needs, developer convenience (returning everything), adding fields without removing them, and trusting frontend filtering.
How do I test for excessive data exposure?
Testing: compare UI data to raw API responses, examine all response fields for sensitive data, check if list endpoints expose more than detail endpoints, verify different roles receive appropriate field sets, and use tools to capture and analyze all API responses.
How do I prevent excessive data exposure?
Prevention: implement response filtering/DTOs, return only fields clients need, use different serializers per role/endpoint, never rely on client-side filtering for security, audit all response fields, and implement data classification to identify sensitive fields.
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