I recently experience this error repeated many times (about once every 11 minutes) in system log (/var/log/message) on FreeBSD system :
cron[xxxxxx]: _secure_path: cannot stat /etc/login.conf: Permission denied
Apparently, it look like the folder /etc lose his permission ; currently 700 (drwx——) and should be 755 (drwxr-xr-x) owned by root and wheel group of course. Just change the permission (not recursively) and it should work :
chmod 755 /etc