The API Security Challenge
APIs power modern digital experiences—from mobile apps to microservices to third-party integrations. This ubiquity makes them prime targets for attackers. The OWASP API Security Top 10 provides a framework for understanding and mitigating API-specific risks.
Critical Risk
94% of applications have API vulnerabilities. API attacks increased 681% in recent years.
OWASP API Security Top 10
Broken Object Level Authorization
BOLA - Most Critical
- Manipulate object IDs
- Access other users' data
- Predictable IDs exploited
Broken Authentication
Account Takeover Risk
- Credential stuffing
- Token theft via XSS
- Missing rate limiting
Broken Property Level Auth
Data Exposure Risk
- Mass assignment attacks
- Sensitive data in responses
- Role escalation
Unrestricted Resource Consumption
DoS & Abuse Risk
- No pagination limits
- Expensive queries
- Resource exhaustion
Top 4 API Vulnerabilities
API1: BOLA
Broken Object Level Authorization
API2: Broken Auth
Weak authentication mechanisms
API3: BOPLA
Broken Property Level Auth
API4: Resource
Unrestricted consumption
Additional Critical Vulnerabilities
API5: Function Auth
Broken function authorization
API6: Business Flow
Unrestricted sensitive flows
API7: SSRF
Server-side request forgery
API8-10
Config, Inventory, Consumption
BOLA Prevention
- Object-level checks - Verify user owns requested resource
- Use UUIDs - Replace sequential IDs with unpredictable ones
- Centralize auth - Consistent policy enforcement
Authentication Best Practices
- Rate limiting - 5 attempts/minute on login
- Short token expiry - 15 min access tokens
- httpOnly cookies - Prevent XSS token theft
API Security Testing Checklist
Security Testing Requirements
Authentication
Authorization
Input Validation
Operational
Defense Strategy
Every API endpoint is an attack surface. Implement authentication, authorization, input validation, and rate limiting on all endpoints without exception.
Conclusion
API security requires a comprehensive approach addressing authentication, authorization, input validation, and operational security. The OWASP API Security Top 10 provides an excellent framework for prioritizing your efforts.
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Written by
Asfaleia Team
Chief Security Researcher
Application security specialist with expertise in API security, OWASP methodologies, and secure development practices.