Server-Side Request Forgery

SSRF occurs when a web application fetches a remote resource without validating the user-supplied URL. It allows an attacker to coerce the application to send a crafted request to an unexpected destination.

Impact

• Access to internal services and metadata APIs
• Internal port scanning
• Remote code execution in some cases
• Data exfiltration

Prevention

• Validate and sanitize all user-supplied URLs
• Use allowlists for permitted domains
• Block requests to private/reserved IP ranges
• Disable unnecessary URL schemes
• Implement network segmentation