On a new Ubuntu 18.04.1 LTS (GNU/Linux 4.15.0-1017-aws x86_64)
, I have installed Google Authenticator [1] and configured it in the following way
/etc/pam.d/sshd
#@include common-auth
...
auth required pam_google_authenticator.so nullok
/etc/ssh/sshd_config
...
ChallengeResponseAuthentication yes
...
AuthenticationMethods publickey,keyboard-interactive
Which works on Ubuntu 16, but not Ubuntu 18 with the following error when trying to log in:
$ ssh ubuntu@server
ubuntu@server: Permission denied (keyboard-interactive).
It seems something has changed with the new version of Ubuntu.
When i enable debug, there is no further information
Aug 17 11:40:31 ip-10-0-0-182 sshd(pam_google_authenticator)[6834]: debug: start of google_authenticator for "ubuntu"
Aug 17 11:40:31 ip-10-0-0-182 sshd[6832]: error: PAM: Permission denied for ubuntu from X.X.X.X
Aug 17 11:40:32 ip-10-0-0-182 sshd[6832]: Connection closed by authenticating user ubuntu X.X.X.X port 61076 [preauth]
ps. The home directory is NOT encrypted
[1] apt-get install libpam-google-authenticator