BSDI BSD/OS 4.0 /FreeBSD 3.2 /NetBSD 1.4 x86 / OpenBSD 2.5 - UFS Secure Level 1

source: https://www.securityfocus.com/bid/510/info In 4.4BSD derivatives there are four secure levels that provide for added filesystem security among other things over and above the regular unix permission systems. Part of the secure levels are the system of file flags which include immutable an...