SSRF is a harmful cyber vulnerability enabling attackers to induce a server to make unintended requests, which could lead to the leaking of sensitive data, access to internal systems, or even remote code execution.
It commonly occurs when an application accepts URLs from unsanitized user input and behaves unexpectedly.
The attacker can employ the vulnerability to scan internal services and identify accessible internal assets and open ports.
The attacker can then access and read the identity access management (IAM) role credentials, take over cloud resources, steal sensitive data from local databases, or even exfiltrate source code.
To avoid such attacks, one should use common headers like “X-Content-Type-Options: nosniff” and “Content-Security-Policy: fetch” to prevent browsers from rendering the response and to limit which destinations the browser can interact with. One should also validate all user inputs and implement robust input validation.