There are many dangers because security on these networks leaves much to be desired. Most of the time, they do not require authentication to establish a connection and their encryption standards are lacking or even non-existent.
The most common threat is the man-in-the-middle attack. The principle is simple: when you connect to a free Wi-Fi service, the hacker hacks the system and is positioned between you and the access point. When you send your data to access your e-mails or your online banking, you are also unwittingly sending it to the cybercriminal. The latter can then gain access to your device (computer, tablet or smartphone) and cause unlimited damage. The cybercriminal can plunder all the content you have on these devices, steal your credentials, transfer data files and install malware. In no time at all, they can block your device or take full control of it.
Another well-known technique is snooping or sniffing. This is also an interception attack. The cybercriminal sets their laptop up near a hotspot (a Wi-Fi access point) and listens illegally to all the signals that pass through it, thanks to a special software kit. They can see and save everything you do online. From this point forward, they will be able to inspect all the recorded data, find the most interesting information such as your usernames and passwords, and divert all your bank accounts.
Finally, the last well-known hackers’ trap is malicious access points. You think you are connected to a legitimate network because of the name of the network. In fact, you clicked on an illegal access point, configured by cybercriminals. They can now view all your sensitive information. They will be able to direct you to a fake website in order to install malware on your computer.