What is external SSRF?

What is external SSRF?

Server-side request forgery (SSRF) vulnerabilities let an attacker send crafted requests from the back-end server of a vulnerable web application. Criminals usually use SSRF attacks to target internal systems that are behind firewalls and are not accessible from the external network. 0.1) of the exploited server.

What methods are you using to prevent server-side request forgery attacks?

One way to protect against SSRF is to blacklist certain domains and IP addresses. This defense technique is not effective, because hackers can use bypasses to avoid your security measures. Below are a few simple ways attackers can bypass blacklists.

What is CSRF and SSRF?

The target of a CSRF attack is the user. While it is accomplished using flaws in how the web application is designed, its purpose is to perform legitimate but unauthorized actions on the user’s account with the web-based service. SSRF forgery, on the other hand, is designed to primarily target the server.

How does the Ssrf attack work?

In an SSRF attack against the server itself, the attacker induces the application to make an HTTP request back to the server that is hosting the application, via its loopback network interface. Here, the server will fetch the contents of the /admin URL and return it to the user.

Is CSRF client or server-side?

A CSRF token is a unique, secret, unpredictable value that is generated by the server-side application and transmitted to the client in such a way that it is included in a subsequent HTTP request made by the client.

Which is an example of server side request forgery ( SSRF )?

Apart from the http:// and https:// URL schemas, an attacker may take advantage of lesser-known or legacy URL schemas to access files on the local system or on the internal network. The following example uses the file:/// URL schema.

How to exploit the server side request forgery vulnerability?

Since the attacker cannot send direct requests to the victim’s server because they are blocked by a firewall, to scan an internal network the attacker has to: Send a request to the vulnerable web server that abuses the SSRF vulnerability. The web server makes a request to the victim’s server which sits behind the firewall.

What can an attacker do with the SSRF vulnerability?

Retrieve sensitive information such as the IP address of the web server behind a reverse proxy. Since the attacker cannot send direct requests to the victim’s server, because they are blocked by a firewall, to scan an internal network the attacker has to: Send a request to the vulnerable web server that abuses the SSRF vulnerability.

How does acunetix solve server side request forgery ( SSRF )?

Acunetix solves this by using AcuMonitor as the intermediary service. During a scan, Acunetix makes requests that contain a unique AcuMonitor URL. If AcuMonitor receives a request on one of these unique URLs, it sends a notification back to Acunetix. It causes Acunetix to raise an alert for SSRF.