Server-Side Request Forgery

Server-Side Request Forgery (SSRF) is a Vulnerability where an attacker manipulates a server to make unauthorised requests to internal or external systems. This can lead to data exposure, system compromise, or unintended actions performed by the server on behalf of the attacker.

In an SSRF attack, the attacker tricks the server into sending a request to an unintended destination. The server, acting as a proxy, may expose sensitive information or interact with internal services that are otherwise not accessible from the outside. For instance, an attacker may use SSRF to access internal network services or metadata endpoints in cloud environments.

SSRF is dangerous because it can bypass traditional security controls like Firewalls, exposing internal services that are typically protected. Attackers can Exploit this Vulnerability to gain unauthorised access to internal systems, retrieve sensitive data, or perform other malicious actions, often without leaving obvious traces. SSRF is particularly harmful in cloud environments where sensitive information, like credentials or metadata, can be exposed.

Preventing SSRF requires proper input validation and restriction of outgoing requests from the server. Organisations should ensure that user input is properly sanitised and validated to prevent malicious requests. Additionally, Firewalls or access control policies should limit the server's ability to make external or internal network requests. Using a deny-by-default policy for outgoing requests is a best practice.

1. Cloud Metadata Exposure: An attacker Exploits SSRF by sending a request to a cloud provider's metadata endpoint, exposing sensitive information such as instance credentials. 2. Internal Network Scanning: SSRF can also be used to make unauthorised requests to internal network services, potentially allowing attackers to map out and Exploit internal systems.

SSRF attacks can lead to the compromise of sensitive data, including credentials, internal services, and metadata. The impact of such attacks can be severe, especially in cloud-based environments where SSRF can bypass traditional perimeter defences. Addressing SSRF vulnerabilities is crucial to prevent unauthorised access and reduce the risk of large-scale system compromise.