Description of problem: The /etc/shadow- file has 0600 permissions. It should be the same as /etc/shadow which is 0000.
shadow-utils-4.1.5.1-1.fc18 has been submitted as an update for Fedora 18. https://admin.fedoraproject.org/updates/shadow-utils-4.1.5.1-1.fc18
Package shadow-utils-4.1.5.1-1.fc18: * should fix your issue, * was pushed to the Fedora 18 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing shadow-utils-4.1.5.1-1.fc18' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2012-14404/shadow-utils-4.1.5.1-1.fc18 then log in and leave karma (feedback).
shadow-utils-4.1.5.1-1.fc18 has been pushed to the Fedora 18 stable repository. If problems still persist, please make note of it in this bug report.