Re: SOLVED: Some users locked out of ssh and sftp?

Ray Olszewski
2005-03-15T16:02:59Z

If this still you, Eve, just from a different e-mail address? Or is this
someone new with (almost) the same problem as Eve?

At 01:23 AM 3/15/2005 -0800, Donald Duckie wrote:

>I got this error message as shown below . . .
>How do I change the /root/.ssh/known_hosts file?
>It seems encrypted . . .

Chuck identified the right first-pass fix here. To expand a bit: go into
the known_hosts file (on the client end, NOT the server end), find the
entry for the target sshd server's system (at the START of each long entry
is one or more identifiers, which could be hostnames, FQDNs, or IP
addresses ... look for 192.168.0.1) and simply delete it. Then your ssh
client will see the connection attempt as a first connection to a new host
and ask you to confirm it manually ... at which point it will do the
required update to known_hosts for you.

The above may not work in your setup, though; as I read the man page, it is
unclear how ssh handles new connections when set to "StrictHostKeyChecking
Yes". If this does NOT work, I suggest a second approach below.

>@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
>@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!
> @
>@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
>IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
>Someone could be eavesdropping on you right now
>(man-in-the-middle attack)!
>It is also possible that the RSA host key has just
>been changed.
>The fingerprint for the RSA key sent by the remote
>host is
>23:52:d4:e8:6a:75:72:ed:78:cb:31:1f:6a:ff:b4:ea.
>Please contact your system administrator.
>Add correct host key in /root/.ssh/known_hosts to get
>rid of this message.
>Offending key in /root/.ssh/known_hosts:7
>RSA host key for 192.168.0.1 has changed and you have
>requested strict checking.
>Host key verification failed.

What is causing your problem is that you (probably) have

StrictHostKeyChecking Yes

in your ssh **client's** config file (/etc/ssh/ssh_config for systemwide
settings, $HOME/.ssh/config for user-specific setting). Change this
setting to

StrictHostKeyChecking Ask

and ssh will ask you if you want to update the key when it sees this sort
of thing, which occurred either because you reinstalled sshd on the host in
question (thereby generating a new server key in
/etc/ssh/ssh_host_rsa_key), or you replaced the host at that hostname,
FQDN, or IP address (whichever way you attempted to connect to it ...
probably IP address, since the message refers to 192.168.0.1).