Issue¶

If you are trying to connect to SSH or trying to do a git pull or push and you see a message like this:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 
@     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 93:a2:1b:1c:6f:3f:68:47:bf:79:56:52:f0:ec:03:6b. 
Please contact your system administrator. 
Add correct host key in /home/user/.ssh/known_hosts to get rid of this message. 
Offending key in /home/user/.ssh/known_hosts:37
RSA host key for host1 has changed and you have requested strict checking. 
Host key verification failed.

Resolution¶

First, be sure that this is not a security issue, that this is not a man-in-the-middle attack.
For this you will need to contact your Network Security Team.

But normally this is related to changes on Acquia server or even you machine.

If that is not the case, you can delete the line that the message is sharing, from the example above:

Offending key in /home/user/.ssh/known_hosts:37

Remove line 37 from the file `/home/user/.ssh/known_hosts` and save the changes.

After you can try again to connect and you will see a new message asking to add a new fingerprint, as you are sure no man in the middle is the case you can accept and you should get connected.

Or you could use a SSH command to resolve this:

ssh-keygen -R [hostname-or-IP]

This method is good if you don't want to manually alter the known_hosts file yourself, and the utility is easier to use if you have multiple hostnames and IP addresses to fix. It can also handle hashed hostnames in a known_hosts.old file.

Cause¶

The message pops out when a changed has occurred, example:

• IP has changed.
• Hostname changed.
• SSH upgrade altered the encryption keys due to a possible security hole.