Modern SSRF Defense Patterns for Cloud-Native Apps

Understanding the Stakes Server-Side Request Forgery (SSRF) turns your infrastructure into a proxy for attackers. In cloud environments, it often leads straight to metadata services, token theft, and lateral movement.

Layer 1: Input Validation and Allow Lists Whitelist destination hosts, enforce URI schemes, and reject requests to private IP ranges. Use DNS resolution on the server side to prevent attackers from bypassing filters with redirects or DNS rebinding.

Layer 2: Network-Level Guardrails Use egress filters, VPC service controls, and firewall rules to block access to internal endpoints from web workloads. Where possible, isolate metadata services behind IMDSv2 or custom proxy layers that require session authentication.

Layer 3: Detection and Response Log outbound requests with full headers. Alert on traffic to known sensitive endpoints, unusual protocols, or high request bursts. During incident response, capture payloads to understand attacker intent.

Conclusion SSRF remains a top OWASP threat. Combining application safeguards with network segmentation and monitoring keeps your tokens and data out of attacker hands.