Server Side Request Forgery (SSRF) is a security vulnerability that allows attackers to exploit a server's ability to make requests, often targeting internal systems behind a firewall. This vulnerability typically arises when user input is used to construct URLs that the server requests, such as in image import functions. An attacker can manipulate the input to make the server send requests to internal or external services, potentially accessing sensitive information or compromising the system. SSRF is challenging to prevent due to the complexity of URI syntax and the variety of protocols that can be exploited, making whitelisting a more effective defensive strategy than blacklisting. The vulnerability is increasingly concerning in cloud environments because it can facilitate unauthorized internal service interactions and lead to Remote Code Execution (RCE). Tools like Detectify help identify SSRF vulnerabilities by using Out-of-Band-Exploitation techniques to detect unauthorized server requests.