What is the default file permission of /etc/shadow in CentOS? Is there any difference in the default file permission of /etc/shadow in previous versions of CentOS?
What is the file permission of /etc/shadow in CentOS?
files;permissions;etc
That's an interesting observation; the only concrete evidence I could find, so far, is this SCAP mailing list thread talking about the change from RHEL5's default permissions of 0400 to RHEL6's default of 0.  You can also observe that in the list of Common Configuration Enumartions on the Working Group's now-archived website.