Theoretically, this could be achieved by saving a user’s password elsewhere, when he or she updates it.
Note that this sort of thing is hardly ever recommendable.
In almost all cases, there is a better architectural approach that renders having to be able to show plain-text passwords unnecessary.
That being said, if you absolutely must do it, this is how it could be done:
funtion wpse_97127_save_passes( $errors, $update, $user )
{
if (
empty( $errors->errors ) &&
! empty ( $_POST['pass1'] )
) {
/* if you must save it in reversible form, at least don't save it in plain-text */
$pass = base64_encode(
mcrypt_encrypt(
MCRYPT_RIJNDAEL_256,
md5(AUTH_KEY),
$_POST['pass1'],
MCRYPT_MODE_CBC,
md5(md5(AUTH_KEY))
)
);
// do something with $pass, i.e. save it somewhere
}
}
add_action( 'user_profile_update_errors', 'wpse_97127_save_passes', 0, 3 );
The above can be reversed like so:
$pass_from_db = $wpdb->get_results( /* retrieve encrypted, but reversible pass from db*/ );
$pass = rtrim(
mcrypt_decrypt(
MCRYPT_RIJNDAEL_256,
md5(AUTH_KEY),
base64_decode($pass_from_db),
MCRYPT_MODE_CBC,
md5(md5(AUTH_KEY))
),
"\0"
);
Please do not do this in production environments with user accounts of individual entities without their consent or knowledge. That would not only constitute bad practice, but also be an unethical deed.
I do the above in exactly one case with one specific user role, the capabilities of which are limited , new users of which are always set up by an admin or other higher level role, and the password of which is shared with multiple people in the first place.
And still I do not feel good about it.