It has become a standard to find an open Wi-Fi network that you can connect your phone or laptop to when you sit down in a coffee shop. For those of us who have limited data plans on our phones, this appears to be the savior we need.

When, in reality, behind the curtain of that free Wi-Fi is the possibility that a enemy lurks in the shadows waiting for the next unsuspecting victim to use the Wi-Fi.

But why is the free, open Wi-Fi network at a coffee shop so dangerous?

Strategies Used That Make Public Wi-Fi Dangerous

To start with, an open Wi-Fi means that anyone off the street can come in and connect to it. That eliminates the issue for attackers where they need to somehow crack the password for the Wi-Fi. Okay, so what can they do now that they’re on the network?

Well, when you connect any of your devices to this Wi-Fi, you’re using that network to access the internet. This means that the information you send from your device travels through that Wi-Fi network, through that router, and then out into the internet.

The router for that network is a sort of middle man for the packets being sent from your device to the targeted website server.

Most people are unaware that there is a popular software that allows any user to watch the traffic on a network, including the packets with your information in them.

This strategy is called packet sniffing and is the main concern when using a public Wi-Fi.

(This picture and more info found here)

The software used, called Wireshark, allows the attacker who is now connected to the same network as your devices to capture a copy, or a snapshot, of the traffic on the network for a certain period of time.

Packet sniffing is most effective when the information sent from your device is not encrypted by whatever application or website is in use.

Theoretically with Wireshark, the attacker could see what websites you log into and the credentials you used if the traffic is not encrypted.

However, most websites or applications have standardized maintaining an encrypted connection.

You can tell when a website is secure and uses encryption for any traffic when you see a lock in the left next to the URL.

(Picture and more information found here)

Another possible danger to using this free coffee shop Wi-Fi is that it wasn’t even the real Wi-Fi for that coffee shop. There is existing technology that allows an attacker to set up a fake network that looks as real as the original.

Then the Wi-Fi you’ve connected to, and told your device to trust, is recording the information you send through it to be used for malicious intent.

Conclusion

Taking all of this into consideration, it is safe to say that public Wi-Fi has the potential to be very dangerous. However, that doesn’t mean it is completely unusable.

If you absolutely need to connect to a public Wi-Fi, here are some tips. Don’t log into any accounts that contain personal information and look into using a VPN that would safeguard your information by encrypting it. More information and tips for using public Wi-Fi can be found here.