Re: Linux Distribution Recomendation

[peter () devbox adamantix org (Peter Busser)]

Hi!

> So ... what is a normal Linux or Unix system and how is the security
> rather poor ?

A normal Linux or UNIX system is a system which provides the standard UNIX
interface.

UNIX was designed for use in a benign research environment. The users were
supposed to be friendly. And the system administrator was supposed to be
trustworthy. If you hack root, you own the system.

If you work on a top-secret document, root can read it, copy it, change it and
delete it. If you forget to set the attributes, then every user on the system
may read and copy it. Even if you do everything right, there is no way the
system will prevent you from making mistakes which may expose the document to
other users. In other words, the security policy depends on the user, not
the system. Because the access control is left at the user's discretion, this
kind of system is called DAC (Discretionary Access Control). Traditional UNIX
access control is DAC.

High-security systems require a more advanced and fine grained access control
system. The security policy is imposed by the system, not by the user. It
should be able to protect top-secret documents against root, if necessary.
Since obeying the policy is mandated by the system, this kind of access control
is called MAC (Mandatory Access Control). UNIX normally does not have any MAC,
except for chroot() (but that is a very primitive and limited MAC that does not
apply to root). Secure level, jail, etc. are all different kinds of MAC.

More flexible MAC policies can be provided by things like Systrace, SELinux and
RSBAC (which is used in Adamantix). Most UNIX vendors also ship UNIX versions
with MAC extensions (such as Trusted Solaris).

> I would consider a FreeBSD system to be a normal Unix
> system in too days perspective and it's level of security as compared
> with other operating systems is very secure.

Maybe todays perspective is not a good reference. Most of todays systems
have been designed for usability and/or performance, not security. The
operating systems that have been designed with security in mind (such as
e.g. Multics and GEMSOS) generally provide a much higher level of security
than normal UNIX or Linux systems. Compared to those systems, a 

> So the way I look at it, if you came up with a base line for security
> based on available out of the box OS you can install. The Unix and Linux
> version would make up the top 30% for being the most secure while
> Microsoft is falling farther behind.

That depends on how you look at it. If you look at the Common Criteria
certification (FYI, CC being a security related certification), you might
conclude that at this moment Microsoft Windows provides more security than
Linux (MS-Windows having CC AEL 4 vs. SuSE Linux having AEL3+). CC is far from
being a perfect comparisson. But it is still more reliable than anecdotal
``evidence''.

Groetjes,
Peter Busser

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