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I've been searching on google and I found other topics like this one (Does https prevent man in the middle attacks by proxy server?) that say man in the middle on public wifi will not be able to decrypt ssl unless the user accepts a security warning about the SSL certificate being invalid. But someone posted the following on reddit and now I'm not sure? Is it really that easy to decrypt with the user seeing nothing like the following seems to say?

It's called a MITM (Man In The Middle) attack, and it's a lot like listening into a phone call from another room in your house.

Basically, the way it works is you "trick" all the devices connected that you are now the router. The device connected to the WiFi has no idea, because your computer is spoofing the MAC address and SSID of the network. To them they're still connected to WiFi and still have internet access.

Meanwhile, on your system, because everyone is now connected to you, and you're forwarding all their requests to the real router, you're basically the router and you can capture all the traffic that goes through you; every single byte. Stripping the SSL is trivial at best, and what you do is "clone" the packets and forward the original to the client. They have no idea because everything checks out (SSL certs and all that are untouched) yet you have still captured the data and "decrypted" it. At that point, everything is basically clear text.

I've demonstrated this to friends pretty much everywhere that has WiFi; McDonalds, Tim Hortons, A&W, their own WiFi at home, you name it. The only sure way to protect yourself is an encrypted VPN, which encrypts the traffic locally before sending it over the network, and is nigh impossible to crack.

marked as duplicate by Steffen Ullrich tls Jan 30 at 20:29

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  • Sounds to me like he doesn't know what he's talking about. He's suggesting a VPN as the solution, which would use TLS, exactly like HTTPS does. – AndrolGenhald Jan 30 at 20:14
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    "Stripping the SSL is trivial at best, ..." - looks like this is talking about sslstrip and not SSL man in the middle (it is man in the middle but not SSL man in the middle). Therefore marked as duplicate of the question which explains how sslstrip works. And no, SSL man in the middle has the same problems in Wifi as it does with a proxy, i.e. the user gets a security warning. – Steffen Ullrich Jan 30 at 20:29

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