Is Your Neighbour Using Your WiFi?

Is Your Neighbour Using Your WiFi?

Ever noticed that pages are loading slowly and wondered if something is amiss? Ever wondered who is on your WiFi? It's possible that someone is using your Wi-Fi without you knowing. You pay good money for your broadband connection and it'd be rather unfair for someone else to be using it behind your back. I'm going to tell you under what circumstances others can gain access to your Wi-Fi and what you can do about it.

The Nature of Wi-Fi

Slightly stating the obvious here, but Wi-Fi is wireless. Unless you live in a metal box then you're going to struggle to keep that bubble of information within your walls. Anyone who's physically close enough to pick up the signal[1] has the ability to intercept it. Though of course they'll need a password... You know, that annoying thing printed on a sticker on the back of the router. Well, actually, in an ideal world they would, but unfortunately the real world isn't perfect and there's known and unknown vulnerabilities. These could allow a 3rd party to access the network (like the recent KRACK vulnerability).

hacker-1
This is what hackers look like... right?

The asymmetric Wi-Fi bubble is (simply put) encrypted with a key. The current Wi-Fi protocol (which is by far the most commonly used) is known as WPA2-PSK which in English is Wi-Fi Protected Access 2 - Pre-Shared Key. The Pre-Shared Key refers to the password you use to connect to the Wi-Fi. As all devices use the same key, all the traffic sent across the Wi-Fi can be decoded by any other device with that key. Given the key is of reasonable complexity (and unless your neighbour wears a dark hoodie and stands in shadows surrounded by random text of the green variety) then chances are that there's no one who would be dedicated and knowledgeable enough to break in to your Wi-Fi network[2] (though I'd keep an eye on the kids).

How to tell who's using your Wi-Fi?

It's a bit easier to tell if someone is connected to your network physically as it's fairly easy to see the Ethernet cable hanging through the window. With Wi-Fi it's a bit tricky but still possible. There's a few ways to do this but the easiest is to look at your router's administration page. The way you get to this varies but the most common ones will be at one of the following IP Addresses:

  • 192.168.1.254
  • 192.168.1.1
  • 192.168.0.1
  • 192.168.2.1

Now, you can work your way through that list but if it's not there or you want to know for certain which it is then you'll need to do the following (this is for Windows):

  1. Press the Windows key + R simultaneously
  2. Type in cmd and press enter
  3. Copy and paste (or type) the following into the window ipconfig | findstr /i "Gateway"

There should be a number which looks like one of the above, this is the IP address of your router. You need to open a browser and type it into the address bar (if you use Edge or Internet Explorer you'll need to prefix it with http://).

Here’s Google Chrome as an example:
ipChrome

Here's how to get to the list of connected devices on a BT Hub 6:

btHubAdminPage

Click on the "My devices" box to the right.

btHubUserList

There'll be a list of the connected devices at the bottom. Some may have what are not immediately identifiable names - I'll be writing a post about how to identify them soon.

Here's how to on the Sky Q Hub:

skyAdminPage

Other Routers

All routers will differ but it's usually easy to find the list on them. If you have trouble finding it, you can always Google your router model.

Conclusion

It's rather unlikely that your neighbour (or anyone else) will have access to your Wi-Fi network unless you have given them the password. As with anything with a password, it's highly advisable to use a strong password of reasonable length in order to vastly reduce the chances of someone guessing (or brute forcing) it. However strong your password may be, it's still advisable to monitor - even infrequently, what devices are connected to your Wi-Fi. Wi-Fi is a bit of a headache in the security world as it really isn't that secure[3] and devices with the password can capture the data sent from other devices on that network.

It's advisable not to share your Wi-Fi network with neighbours as they can quickly eat up your allowance (if you have one) but also use a chunk of your broadband's speed when they're using it (plus it's against many ISP's terms and conditions to share Wi-Fi with a neighbour, not to mention that you're responsible for what they use it for).

If your broadband is slow, it's worth checking to see what devices are connected to it even if it's not any of your neighbours. Consumer Wi-Fi routers aren't particularly good at handling connections from multiple devices and may slow down or even drop connections. Also, you may well find that if you're a BT customer then BT Wi-Fi is enabled on your router, anyone connected to this network from your Hub will be using your line (but will not be able to view what you're doing or use your allowance). This will however impact the speed available to you and as such you may wish to disable this.

Short Link: on-te.ch/nwi


  1. Bonus side note: It's worth noting that as Wi-Fi is a two-way stream (devices talk back), the range of Wi-Fi is limited by the signal strength of the client device. It's possible to have Wi-Fi networks that work over incredibly long distances. ↩︎

  2. The Wi-Fi "cracks" generally rely on what is known as "brute force" whereby the tool tries many different passwords until it finds the right one. This is why the default passwords are getting longer and more complex. Also, there's a button on a lot of routers that you can press to connect a printer or other device without entering the password. This protocol is known as WPS (Wireless Protected Setup) and is usually incredibly easy to crack. It's a great example of how security and simplicity are two things that don't like to coexist. ↩︎

  3. Security features such as hiding the SSID or MAC address filtering aren't worth it as they only give the impression you're trying to hide something and really don't do anything to improve security. ↩︎

Owen Nelson

Owen Nelson

https://owennelson.co.uk

IT Systems Administrator from Northamptonshire, UK. Always on the lookout for ways to make things faster and more secure - and I enjoy getting through a fair bit of Tea along the way.

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