According to the definition provided by OWASP, a SSRF attack enables an attacker to abuse a server’s functionality to read or update internal resources.

“The attacker can supply or modify a URL which the code running on the server will read or submit data to, and by carefully selecting the URLs, the attacker may be able to read server configuration such as AWS metadata, connect to internal services like http enabled databases or perform post requests towards internal services which are not intended to be exposed,” OWASP explains.