[nycbug-talk] How secure: wireless + ssh?

Chris Buechler nycbug
Mon Dec 26 02:04:34 EST 2005

Francisco Reyes wrote:

> Had never had the need for wireless..
> Getting a new laptop and was wondering how safe it is to use a 
> wireless WEP connection with SSH.

This has been pretty much beaten to death, but there's one quick point 
I'd like to throw in.  Always connect to any SSH server on a trusted 
network first, so it saves the server's key.  Watch out for key 
warnings, where the host key does not match the one you have saved.  If 
you get that on an untrusted network, watch out.  sshmitm, part of the 
dsniff [1] suite, allows man in the middle attacks against SSH if you 
are tricked into accepting the "changed" host key.  An attacker can use 
ARP poisoning, amongst other tactics, to route your connections through 
his machine, and accepting the attacker's host key means you have 
nothing more than a SSH connection to his machine, which then relays 
everything to the legit SSH server (with everything, of course, being 
captured, unencrypted, by the attacker). 

1 - http://www.monkey.org/~dugsong/dsniff/


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