You connect to a cafe's free WiFi and log into your bank. Someone at the next table may be watching every packet you send with a cheap sniffer. This is not a movie scene — public WiFi is far more dangerous than it looks.
The fatal flaw of public networks is that they are often unencrypted or use a widely known password, letting anyone on the same network eavesdrop on your traffic.
1. The danger of public WiFi
Home WiFi has a password and encryption, keeping strangers out. Public WiFi is open or shared, so attackers can join the same network and hijack traffic with ARP spoofing or a fake hotspot.
2. Common attack methods
The two most common are a "rogue hotspot" and a "man-in-the-middle attack". The former sets up a fake hotspot with a name similar to the venue's WiFi; the latter tampers with routing so you think you are talking to a site while an eavesdropper sits in between.
| Method | Principle | Harm |
|---|---|---|
| Rogue hotspot | Fake hotspot lures you in | All traffic captured |
| MITM attack | Tampered routing | Credentials stolen |
| ARP spoofing | Fake gateway | Traffic redirected |
3. Six-step protection
First, open a VPN before connecting to any public WiFi. Second, protect traffic with ProtonVPN's AES-256 tunnel. Third, only enter passwords after the VPN is on. Fourth, enable NetShield to block malicious domains. Fifth, use Secure Core for sensitive operations. Sixth, disconnect and clear saved networks when done.
A frequent business traveler shared that after connecting to a "free WiFi" at an airport, his phone immediately showed a suspicious login alert. After switching to ProtonVPN, such risks disappeared. Public WiFi is not scary — browsing in the open is.
Back to that cafe: before joining the free WiFi, connect to ProtonVPN first. The tunnel wraps your data in ciphertext that sniffers cannot read.
