Securing AI-Powered Interfaces

AI API Security

Security guidance for teams building and consuming AI APIs — covering authentication, prompt injection defenses, rate limiting, and data handling.

Overview

AI APIs introduce unique security challenges beyond traditional API security. When applications integrate with Large Language Models, they must defend against prompt injection, manage sensitive data in prompts and responses, and handle the non-deterministic nature of AI outputs.

Key Risk Areas

RiskImpactOWASP Reference
Prompt InjectionAttacker manipulates AI behavior via crafted inputLLM01
Sensitive Data DisclosureAI reveals training data or context window contentsLLM02
Excessive AgencyAI takes unauthorized actions via tool useLLM08
Unbounded ConsumptionResource exhaustion through AI API abuseLLM10
Supply ChainCompromised plugins, models, or data sourcesLLM03

Security Controls

Authentication & Authorization

  • API key rotation policies
  • Scoped tokens with minimal permissions
  • Per-user rate limiting and quota enforcement

Input Validation

  • Prompt injection detection layers
  • Input sanitization before AI processing
  • Content length and complexity limits

Output Handling

  • Response filtering for sensitive data patterns
  • Output validation before downstream consumption
  • Structured output enforcement (JSON schemas)

Monitoring & Observability

  • Token usage tracking and anomaly detection
  • Prompt/response logging (with PII redaction)
  • Cost monitoring and alerting thresholds

Guides

Detailed guides are under development.

GuideStatusDescription
API Gateway Configuration for AIPlannedRate limiting, auth, and filtering patterns
Prompt Injection Defense PatternsPlannedMulti-layer defense strategies
AI API Threat ModelPlannedSTRIDE-based threat model for AI integrations
Secure AI SDK UsagePlannedBest practices for Anthropic, OpenAI, and other SDKs

Regulatory Considerations

  • GDPR Article 22: Automated decision-making requirements
  • EU AI Act: Transparency obligations for AI system providers
  • Data residency: Ensuring AI API calls respect data sovereignty requirements