Public WiFi Networks: Why Your Data is at Risk

You are sitting at the airport trying to check your email. You see several available WiFi networks and connect without thinking about it. It seems completely harmless, but behind the scenes, something much more dangerous could be happening. Public WiFi networks are a welcome convenience for many travelers and digital nomads, but they also conceal a range of cybersecurity threats that most of us do not fully understand.

What makes your devices vulnerable on public networks?

The difference between a home network and a public hotspot is dramatic from a security perspective. In a home network, it is usually only your own devices that are connected, and you control all the traffic yourself. On a public WiFi, however, anyone can connect. There is no verification, no control. For a cybercriminal, this is a goldmine of opportunities to access others' data.

Most public WiFi networks also lack encryption. This means that the information sent between your device and the network can be intercepted by anyone nearby with the right technology. Your browser history, your emails, your login credentials – everything can potentially be captured.

The Most Dangerous Attack Forms Against Public WiFi

The middleman tricks you into a fake website

This type of attack is called a man-in-the-middle attack and works like this: an attacker intercepts the communication between your device and a web server, such as your internet bank. Then, they create a fake copy of the webpage you are trying to reach – one that looks almost identical. You never realize the difference and log in with your real credentials. The result? The attacker now has access to your account.

The thought of someone stealing your bank login details is concerning enough, but it can get worse. With access to your email, an attacker can send fraudulent emails to your contacts, spread viruses, or gain access to other sensitive accounts linked to the email address.

WiFi eavesdropping through fake networks

A classic method is called “Evil Twin” – an attacker creates a fake WiFi network with a name similar to a legitimate network. Imagine you walk into a café and see these network names: CoffeeShop, CoffeeShop1, CoffeeShop2. How do you know which one is the genuine one? The likelihood is that at least one of them is a trap.

When someone connects to the fake network, the attacker can monitor all traffic from that person: web history, passwords, credit card numbers, personal messages. This type of WiFi eavesdropping is extremely effective for cybercriminals because it is passive – they just need to sit there and collect data.

Packet sniffing: When software becomes a weapon

Packet sniffing programs are actually legitimate IT tools used to diagnose network issues. But in the hands of a cybercriminal, they become something entirely different. These programs capture all data packet traffic sent over the network and analyze the content.

The dangerous thing is that it is not visible to the victims. You can use public WiFi completely normally, without noticing anything suspicious. But months later, you might suddenly find out that your identity has been stolen, or that your company's secret information has leaked online.

Cookie theft and session hijacking

Cookies are small data files that websites store on your device. They are convenient – they allow you to stay logged in without having to enter your password every time. However, on public WiFi, an attacker can steal these cookies.

If an attacker manages to steal your session cookie from, for example, your email service or online bank, they can use it to log into your account without needing your password. This is called session hijacking and is particularly common on public networks where traffic is easy to intercept. The attacker can then access your personal messages, transfers, or other sensitive data.

How to Protect Yourself on Public WiFi Networks

Disable automatic connection: Turn off the feature that allows your device to automatically connect to available WiFi networks. This prevents you from inadvertently connecting to a fake network.

Verify network with staff: Always ask an employee which WiFi networks are legitimate before connecting. Do not trust the network name itself.

Disable file sharing: Deactivate file sharing options on your device and log out of services you are not actively using.

Use password-protected WiFi when possible: If the option is available, always choose a WiFi network that requires a password over an open one.

Use VPN: A Virtual Private Network (VPN) encrypts all traffic from your device and makes it practically impossible for others to eavesdrop. This is especially important if you need access to sensitive or business-critical information.

Use HTTPS websites: Websites that use the HTTPS protocol encrypt the traffic between your device and the server. However, some sophisticated attackers can spoof HTTPS, so this measure is not foolproof.

Avoid financial transactions: Never perform bank transactions, online shopping, or cryptocurrency transactions on public WiFi unless absolutely necessary.

Keep the system updated: Make sure your operating system, browser, and antivirus software are fully updated with the latest security patches.

Turn off WiFi and Bluetooth when not in use: If you are not actively using these features, turn them off to reduce the attack surface.

Conclusion: Be aware of the risks

Cybercriminals are constantly developing new ways to access your personal data. Public WiFi networks are one of their favorite hunting grounds precisely because many users are unaware of the dangers.

By understanding how these attacks work – from man-in-the-middle attacks to WiFi eavesdropping and cookie theft – you can protect yourself. There is no completely risk-free solution, but a combination of caution, the right tools like VPN, and updated security software can dramatically reduce risks. Next time you're on the go and see a friendly WiFi network, think twice before connecting.