What is SSRF

SSRF (Server-Side Request Forgery) is a vulnerability where an attacker manipulates a server into making HTTP requests to unintended destinations, such as localhost, internal/private IPs, or cloud metadata services. SSRF can target the local server or other internal systems and may expose sensitive resources that are inaccessible from the internet. Common bypass techniques include alternative IP representations, DNS tricks, URL encoding/double encoding, redirects, URL parsing inconsistencies, and open-redirect chaining to bypass blacklist or whitelist filters. Blind SSRF occurs when the server makes the request but does not return the response directly. When hunting for SSRF, look beyond parameters named url and check webhooks, file/RSS imports, image and PDF generators, Open Graph previews, OAuth/OIDC discovery, SAML metadata, headers such as Referer, and any user-controlled input that could cause the backend to make an outbound request.