LinuxHostingSupport

Sometimes SSH won’t allow you to login though correct login credentials has been submitted and the SSH access logs says the following:

sshd: PAM _pam_load_conf_file: unable to open /etc/pam.d/system-auth 
sshd: PAM unable to dlopen(<*unknown module path*>) 
sshd: PAM [error: <*unknown module path*>: cannot open shared object 
file: No such file or directory] 
sshd: PAM adding faulty module: <*unknown module path*>

The SSH access logs are saved in the /var/log/secure file. The logs clearly indicates that the file “system-auth” is missing from the “/etc/pam.d/” directory. This file is responsible for calling the PAM modules and is very much needed for authentication.

root@server [~]# ls -la /etc/pam.d/system-auth 
 /bin/ls: /etc/pam.d/system-auth: No such file or directory

In order to fix the issue, copy over the ‘system-auth’ file from another server and you should be able to SSH in immediately.