Restoring backups of a domains shadow and passwd files

Symptoms

Under the Email Accounts interface in cPanel, the list of email accounts displayed may need to be included for an entire domain, or only a single or a few addresses will show.

Furthermore, any attempts to recreate the missing accounts result in an error stating the accounts already exists.

Description 

If a domain's passwd file is modified or damaged, it can result in email accounts not showing in the cPanel interface and cause authentication errors for the email users.

Restoring a backup of the shadow and passwd files is the only way to restore the domain's previous passwords.

Workaround

Please note that "$user" is the cPanel account in the below commands, and "domain.tld" is the domain you're working with.

A backup of the damaged file can be restored to restore the email account list and passwords. Relevant files are found inside a cPanel backup under the following paths:

$user/homedir/etc/domain.tld/passwd
$user/homedir/etc/domain.tld/shadow

Extract the passwd and shadow files from a cPanel backup file

tar -xf $user.tar.gz $user/homedir/etc

This extracts all domain's passwd and shadow files into the current working directory, in the $user/homedir/etc folder.

Move the files you're replacing to another directory to back them up. In this example, I am creating a backup folder in /root to use:

mkdir /root/backup

mv -v /home/$user/etc/domain.tld/{shadow,passwd}  /root/backup/

Now you can copy the backed-up files into the domain's etc folder:

cp -v $user/homedir/etc/domain.tld/{shadow,passwd} /home/sean/etc/domain.tld/

cPanel's email account cache needs to be moved aside now to the /root/backup directory we created earlier:

 mv -v /home/$user/.cpanel/email_accounts_count /home/$user/.cpanel/email_accounts.json /root/backup

Lastly, the Dovecot authentication cache must be cleared to force users to use the new passwords.

doveadm auth cache flush