Server-Side Request Forgery (SSRF)

Server-Side Request Forgery (SSRF) is a vulnerability that allows an attacker to induce a server-side application to make requests to an unintended location. This can be used to bypass firewalls, access internal services, and exfiltrate data.

Common Types of SSRF Vulnerabilities

• Basic SSRF: The application's response reveals the response from the back-end server.
• Blind SSRF: The application's response does not reveal the response from the back-end server.

Prevention Methods

• Whitelisting: The most effective way to prevent SSRF is to use a whitelist of trusted domains.
• Input Validation: If you cannot use a whitelist, you should validate all user-supplied input to ensure that it is a valid URL and that it does not contain any malicious characters.
• Disable Unused URL Schemes: You should disable any URL schemes that are not absolutely necessary.
• Use a Proxy: You can use a proxy to route all outgoing requests through a single point of control.