On a VM I am initializing I am able to log in as one non-root user (admin
) but not another (tbbscraper
) over SSH with public key authentication. The only error message I can find in any log file is
Sep 18 17:21:04 [REDACTED] sshd[18942]: fatal: Access denied for user tbbscraper by PAM account configuration [preauth]
On the client side, the syndrome is
$ ssh -v -i [REDACTED] tbbscraper@[REDACTED]
...
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering public key: [REDACTED]
debug1: Authentications that can continue: publickey
debug1: Trying private key: [REDACTED]
debug1: read PEM private key done: type RSA
Connection closed by [REDACTED]
Changing 'tbbscraper' to 'admin' allows a successful login: debug1: Authentication succeeded (publickey).
appears instead of the "Connection closed" message.
This doesn't seem to be a permissions problem...
# for x in admin tbbscraper
> do ls -adl /home/$x /home/$x/.ssh /home/$x/.ssh/authorized_keys
> done
drwxr-xr-x 3 admin admin 4096 Sep 18 17:19 /home/admin
drwx------ 2 admin admin 4096 Sep 18 16:53 /home/admin/.ssh
-rw------- 1 admin admin 398 Sep 18 17:19 /home/admin/.ssh/authorized_keys
drwxr-xr-x 3 tbbscraper tbbscraper 4096 Sep 18 17:18 /home/tbbscraper
drwx------ 2 tbbscraper tbbscraper 4096 Sep 18 17:18 /home/tbbscraper/.ssh
-rw------- 1 tbbscraper tbbscraper 398 Sep 18 17:18 /home/tbbscraper/.ssh/authorized_keys
# cmp /home/{admin,tbbscraper}/.ssh/authorized_keys ; echo $?
0
... nor a PAM-level access control problem ...
# egrep -v '^(#|$)' /etc/security/*.conf
#
... so none of the existing answers to similar questions would seem to apply. The only other piece of evidence I've got is:
root@[REDACTED] # su - admin
admin@[REDACTED] $
but
root@[REDACTED] # su - tbbscraper
su: Authentication failure
(Ignored)
tbbscraper@[REDACTED] $
which suggests some larger-scale PAM issue, but I can't find anything obviously wrong with the stuff in /etc/pam.d
. Any ideas?
The VM is an EC2 instance, OS is Debian 7.1 (Amazon's off-the-shelf AMI).