DZone

Server-side request forgery (SSRF) attacks are yet another form of cyber-crime, and they are designed to specifically target a server by sending back-end requests from vulnerable web applications. These attacks can threaten not only servers, but other connected confidential information such as cloud services in AWS, Azure, and OpenStack as well. They can be especially challenging to battle since they are generally used to target internal systems protected by firewalls that are inaccessible from the external network; by directing these strikes, the attacker has the potential to gain full or partial control of the requests sent by a web application.

There are multiple approaches that the malicious user may take in a typical SSRF attack; a frequently seen example is by inducing the server to create a connection back to itself or external third-party services. From here, the attacker can seize control of the third-party service URL to which the web application makes a request. Other examples include making requests to internal resources, running port scans on internal IPs, and more. These attacks exploit relationships that your server has built, inciting trust only to strike the vulnerable application and carry out their own agenda.

Source: DZone