ssmtp: world-readable password file

From the Red Hat bugzilla entry:

In order to have ssmtp working for every user on the machine, the file /etc/ssmtp/ssmtp.conf must be readable by every user (others must at least have the read right to this file).

If an authentication smtp server is used (as gmail for example), the login and password appears in clear text in ssmtp.conf. This is obviously a security problem.