[blincoln]

It's not that someone can set up a MitM device. Wifi with a shared password can be passively captured using a variety of tools and decrypted using WireShark.[1]

The "coffee shop" scenario, where a WPA2 Personal password is written where anyone can see it, is essentially as insecure as non-encrypted wireless.

WPA2 Personal is only secure if the password is very strong[2] and never given to untrusted parties.

The only wireless security I put any real trust in is WPA2 Enterprise with 802.1x certificate-based authentication specifically.[3]

[1] https://wiki.wireshark.org/HowToDecrypt802.11 [2] Otherwise it's possible to mount a hash-cracking attack after capturing the four-way handshake for clients that have the password. [3] WPA2 Enterprise with per-user password-based authentication is vulnerable to an "evil twin attack" unless the password is very strong, which is usually not the case, because organizations typically have it authenticate against Active Directory or another LDAP.

[zielmicha]

> The only wireless security I put any real trust in is WPA2 Enterprise with 802.1x certificate-based authentication specifically.

802.1x with a certificate for Radius server (TTLS mode, which simply layers the plaintext password via TLS) and plain passwords for users is also good enough.