Looks like Vocera's wireless LAN VoIP communicators don't bother to
cryptographically confirm the validity of a digital certificate because
it's too much "processing overhead required".  This is clearly stated in
the Vocera documentation.  I am also waiting for verification on Cisco's
wireless VoIP handsets.  I heard that the Cisco devices have the same
design flaw, but it's fairly simple to confirm if you have one of those
wireless LAN VoIP handsets.

That means you can basically put up your own bogus access point with a
rogue RADIUS backend with your own self-signed digital certificate
claiming it's the same as the certificate the client is use to seeing.
Since the client never bothers to cryptographically check the signature,
it thinks it's talking to the right server and it will send its hashed
password or pin to the server making it very easy to crack.


I have more details here:
https://blogs.zdnet.com/security/?p=896



George Ou