Free WiFi is a hacker's favorite hunting ground. Here's what most guests never see happening around them.

On open networks, attackers don't need to break encryption. They just need one weak link, and the captive portal, the one page almost everyone passes through to get online, is usually it. A fake login page harvesting your number and email. A spoofed MAC address borrowing someone else's paid session. Forged ARP replies quietly rerouting every device's traffic through an attacker's laptop. A stolen session token replayed from across the room.

We sat down and mapped out exactly how each of these attacks works, then closed every one of them, specifically for ISN Free WiFi.

Every unlock command to the router is HMAC signed and verified with a timing safe comparison, so there's no URL to copy and no signature to guess your way into. Guest devices are isolated from each other at the wireless layer, so ARP spoofing between two people on the same WiFi has nowhere to go. MAC recognition is rate limited, so a spoofed address can't be milked for free access. Session tokens are short lived, single use, and mapped to one device, so a stolen one is worthless to anyone but its original owner. DNS tunneling out of the guest network is blocked at the firewall. The router's own admin panel is walled off from guest devices entirely. And Cloudflare sits in front of everything, filtering hostile traffic before it ever reaches our servers.

None of this is theoretical. It's the same 12 attack patterns real captive portals get hit with, documented and defended against one by one.

Free WiFi shouldn't come with a free education in how you got hacked.

See exactly how it works: ISN Free WiFi Security