Re: PuTTY failing "Server's host key did not match the signature supplied" suddenly

On Mar 10, 9:13 am, comph...@xxxxxxxxx (Todd H.) wrote:
Raymond <rpa...@xxxxxxxxx> writes:
Dear All,

PuTTY suddenly fails to connect to my server reporting "Server's host
key did not match the signature supplied".

Configuration as follows:

PuTTY Version: Release 0.60

Server: CentOS release 5 (Final) with openssh-server-4.3p2-24.el5
openssh-4.3p2-24.el5

Tried connecting with ssh client and ssh reports:
"hash mismatch
key_verify failed for server_host_key"

or

"RSA_public_decrypt failed: error:0407006A:rsa
routines:RSA_padding_check_PKCS1_type_1:block type is not 01
key_verify failed for server_host_key"

Have anyone encountered this problem before?

When did you create the profile? Did the server's key perhaps simply
change from then until now?

Be sure to verify the new server signature with an admin or user of
that box to verify that you aren't being MITM'd.

ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key.pub
ssh-keygen -l -f /etc/ssh/ssh_host_dsa_key.pub

Is the command for a user on the machine to list out the
fingerprints.

--
Todd H.http://www.toddh.net/

Ok, this is what I get:

# ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key.pub
2048 4b:22:b7:31:73:66:64:07:c5:2d:51:3e:69:82:9e:53 /etc/ssh/
ssh_host_rsa_key.pub
# ssh-keygen -l -f /etc/ssh/ssh_host_dsa_key.pub
1024 fb:23:96:4f:96:fa:ca:3a:d1:a2:d3:69:96:a0:7c:1e /etc/ssh/
ssh_host_dsa_key.pub

switch to a normal user:
$ ssh mydomainname.com
The authenticity of host 'mydomainname.com (00.000.000.000)' can't be
established.
RSA key fingerprint is 4b:22:b7:31:73:66:64:07:c5:2d:51:3e:69:82:9e:
53.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'mydomainname.com,00.000.000.000' (RSA) to
the list of known hosts.
hash mismatch
key_verify failed for server_host_key

$ ssh localhost
The authenticity of host 'localhost (127.0.0.1)' can't be established.
RSA key fingerprint is 4b:22:b7:31:73:66:64:07:c5:2d:51:3e:69:82:9e:
53.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'localhost' (RSA) to the list of known
hosts.
hash mismatch
key_verify failed for server_host_key

The strange thing is, if I tried hard enough, retrying the connection
repeatedly, it will sometimes get connected.
Both openssh client and PuTTY exhibit the same problem. I would think
that the problem lies with openssh server then.

How do I troubleshoot this kind of problem? Any logs that I can watch?

Regards,

Raymond Pau
.