His main thesis was basically that every OS in common use today, from Windows to UNIX variants, has a fundamental flaw in the way privileges and permissions are handled - the concept of superuser/administrator. He argued instead that OSes should be redesigned to implement the principle of least privilege from the ground up, down to

the

architecture they run on. OpenSSH's PrivSep (now making its way into other daemons in the OpenBSD tree) is a step in the right direction.

Capability-based systems like EROS-OS are a way of addressing this issue. Have a look at http://www.eros-os.org/ If you only read one article then pick this summary from IEEE Software magazine http://www.eros-os.org/papers/IEEE-Software-Jan-2002.pdf The slammer worm made its way into some very unexpected places. It seems that in many organizations, once the UDP packet made its way to one MS-SQL server through one hole, it then acquired all the privileges of the IP address that supposedly belonged to a database server. Since traffic from the database server was considered to be trustworthy, it was able to easily reach and infect many more internal MS-SQL servers that were on internal networks unconnected to the Internet. In other words, there were MS-SQL servers acting as Application Layer Gateways to transport the worm into protected networks. The random nature of the addresses chosen by the worm virtually guaranteed that every single network path in the world containing MS-SQL servers would be infected. --Michael Dillon