Re: Fix Security (was: Paging file)

On Wed, 30 Oct 2002 vhamberg@attbi.com wrote:

> Is not *nix just as prone to tampering by someone with
> sufficient authority (stolen or not) who can go in and
> do almost anything to anybody? You need to have
> authorization now to get into SST - before V5R1 that was
> a problem, except that it is shipped with *PUBLIC
> *EXCLUDE. But if someone gets the *nix 'root' password,
> or can get superuser rights, they're in, and it's really
> easy to mess with executables in *nix - just cat 2 files
> together, or cat what you want to replace whatever.

Not all *nix are the same in this regard.  OpenBSD is a particularly good
example of a system that has a lot of ways to protect the system from
someone who has obtained too much authority.

An example of how many unix systems deal with programs/users who have
obtained too much authority is what is called a "chroot jail".  Programs
such as BIND and ftp are often run with super-user (root) authority.  This
is required as they open ports below 1024 [1].  Both BIND and ftpd have a
colorful security history.  In the past (and possibly in the future)
people have been able to obtain root authority by exploiting flaws in
these programs.  However, if run in a chroot jail they can only affect
those parts of the system that is also in the jail *even though they are
the super-user*.  Not even root can get outside the chroot jail.

Of course I wonder if OS/400 has a similar ability?

Other *nix (like OpenBSD) implement "privilege elevation" on a very
selective level.  I believe OS/400 has the same abilities here.  For
example a process running with regular user authority can be elevated to
be able to open low numbered ports.  This way small amounts of elevated
authority can be granted without giving away the whole enchilada.  Again,
I think OS/400 can do the same thing.

And it's really easy to mess with executables on OS/400, too.  They OS may
not load them, but you can mess with them.  Of course if they can't be
loaded it's not too much fun, unless you enjoy the look of horror on
people's faces when things stop working...

[1] Not really true.  BIND and ftp can be started after root has opened
the ports for them, allowing the programs themselves to run without root
authority.

James Rich