Router Vulnerability Check

The Router Vulnerability Check Tool is used to check the router setup and find open ports via UPnP and NAT-PMP which may lead to external access. The feature also gives the possibility to close the open ports you may find. 

This feature is available for all Premium users. For more information on Fing Premium, check out our dedicated webpage. 

Router Setup and Open Ports Explained 

For data to pass between the Internet and your network, the information must travel through virtual ‘holes’ in the router’s software, called ports. Ports not only allow the information to pass in and out of your network, but they also direct the information to the correct devices. 

Think of your router as being like your house – a port is like your front door. The door sits shut unless you want someone to access your house. Like with a front door, a port is only opened if it is being used. But also like a door, if a port is weak or left open then you are leaving yourself vulnerable to intruders. 

There are 65,535 ports on your router but no worries, they are not all permanently open. 

Secure ports are either opened manually by the owner of the network or by inbuilt protocols, such as UPnP and NAT-PMP. These protocols are designed to save users the effort of having to manually open ports – they give permission to the devices within the network to open ports on their own. 

How Does the Router Vulnerability Check Work? 

The Router Vulnerability Check is made up of two parts: 

• The Remote Scan Test performs a port scan on your public Internet address (the individual numerical address visible to the public when you are online) to see which ports are open to the external world: these are the open doors into your home, and you should make sure to have only the strictly necessary ones open. 
• The Internal Router Audit checks the router addresses, the NAT configuration and whether UPnP or NAT-PMP is activated. In the house metaphor, this would be the equivalent of checking the security measures placed inside the building in case an intruder did make it through the door. 

How To Perform a Manual Router Vulnerability Check 

On both mobile and desktop applications, you will find this feature in the Tools tab, under the “Improve your network security” section.  

Once the check is completed, you’ll be able to see: 

• Details about your router 
• Details about your setup 
• Open ports on your router (only if vulnerabilities are detected) 

If any open port is identified, you will be able to select it and close it manually. For reference, see the image below.

Automated Router Vulnerability Checks 

The Automated Router Vulnerability Check is a feature for Fing Desktop and Fingbox, but you can also take advantage of it on Fing App. To access it on mobile, you must pair your Fing App with Fing Desktop first.  

After that, you will find an area dedicated to automated vulnerability tests in the Security Tab.

This will come with the option to schedule the tests (every day, every other day or every week) and quick access to the timeline of the last events.

You can also check out our YouTube tutorial on How to Schedule Automated Router Vulnerability Tests.

Definitions 

Port Forwarding 

Port forwarding or port mapping is an application of network address translation (NAT) that redirects a communication request from one address and port number combination to another while the packets are traversing a network gateway, such as a router or firewall. 

UPnP 

Universal Plug and Play (UPnP) is a network protocol that allows compliant devices to automatically set Port forwarding rules for themselves. These devices can be personal computers, printers, security cameras, game consoles, or mobile devices that communicate with each other and share data over your network.  

To disable UPnP, you will need to access your router's setup page using a web browser. You will likely find the UPnP settings under Advanced Network settings. 

NAT-PMP 

Nat-PMP is a similar protocol to UPnP, in that it allows compliant devices to automatically set Port forwarding rules for themselves. 
To disable NAT-PMP, you will need to access your router's setup page using a web browser. You will likely find the NAT-PMP settings under Advanced Network settings. 

UPnP & NAT-PMP Risks 

The reason why these protocols are considered a vulnerability is that through your devices when these are enabled, they can essentially poke holes in the Router Firewall, meaning if a device becomes compromised through hacking or malware you leave your router open for vulnerabilities.  

These protocols allow opening ports and creating port mapping and forwarding automatically, without any authentication.  

Open Ports via UPnP or NAT-PMP 

When your router allows UPnP or NAT-PMP port forwarding, some programs or applications may open or leave open ports redirecting a communication request from one address and port number combination to another.  

An open port refers to a TCP (Transmission Control Protocol) or UDP (User Datagram Protocol) port number that is actively accepting packets. (UPnP & NAT-PMP are both samples of TCPs). In other words, behind it is a system that is receiving communication. A closed port, on the other hand, rejects or ignores packets.