> Man in the middle is actually one of the most difficult to setup and > have actually productive. You would probably have to be the end > user's ISP to do it effectively.
I disagree. I've seen it done, and it wasn't that difficult. The server in question did not use SSL at all. If it had a mechanism for encryption with no authentication (as a few people have been claiming to be desirable), it wouldn't have helped. With a CA-signed cert, the perps couldn't have gotten away with it. In this specific case, the perps broke into the name server at the ISP (using an IIS vulnerability) and changed the A record for the customer's server to point to their own server. Whenever someone connected to port 80 on this MITM server, it would open a port 80 connection to the real server and pass data both ways. But they probably logged the data. It was detected about two weeks later when someone looked at the server logs and noticed that every HTTP request for those two weeks came from the same IP address. Note that even the CA procedures that some people consider lax (only verifying domain authority) would have been sufficient to prevent this attack. There are several other reasonably simple threat scenarios which can be averted by use of proper certs but not by use of non-authenticated encryption. Hence my claim that non-authenticated encryption is almost worthless. Perhaps worse than worthless, since it will give people a false sense of security. Eric
