So another engineer buddy of mine and I were having a drink the other night. He mentioned that you're allowed to use personal devices on the office wifi, but that they install a custom certificate so they can MITM your traffic.
Neither of us are security experts, but I know a little bit about the HTTP/TLS handshake protocol to question whether this is the case.
As far as I understand it (please forgive me if I butcher it):
Client-Server initiate handshake, and exchange certificate from signing authority + public key + random string.
Public key is used to decrypt a random string of characters, which is fed into a hashing algorithm and reveals a private key.
Private key is used to decrypt the traffic that follows
We were reading this article, about how companies sometimes install certificates to decrypt outgoing traffic.
If the blog-post case is true, then how does this work? Would they get the private key using their trusted-root all uses certificate? Assuming that works, that covers the windows use-case, but what about other platforms like OSX/iOS, linux, BSD etc.?
Are there other approaches that I'm not considering, where a certificate install could be used to MitM?