Not to continue offtopic for too much longer, but IMHO, the "only root
can bind to ports under 1025" was, and continues to be, a terrible UNIX
hack that was possibly reasonable at its time of inception, but that has
since *caused* more security holes than it ever helped to prevent.  The
argument for the hack is backwards compatibility, any other explanation
usually ends up as rationalization or circular logic.  My $.02.

> -----Original Message-----
> From: Bill Anderson [mailto:[EMAIL PROTECTED]]
> Sent: Sunday, July 30, 2000 5:04 PM
> To: [EMAIL PROTECTED]
> Subject: Re: [Zope] Starting Zope
> 
> 
> 
> (Quoting reversed for sake of continuity.
> 
> > On Sun, 30 Jul 2000, Cary O'Brien wrote:
> > 
> > > > Cary O'Brien wrote:
> > > >
> > > > > Well...
> > > > >
> > > > > If you are running on Linux you could simply edit the 
> kernel code to
> > > > > elimitate the check on being root to bind to low 
> ports.  That's what
> > > > > we did.
> > > >
> > > > Which is an even worse idea.
> > > >
> > >
> > > Why?  On a sufficiently firewalled off box, where the few 
> logins are
> > > completly trusted, what's the diff?  If you were worried 
> about people
> > > cracking a user account and getting underneath telnet, 
> than limit the
> > > lifting of the restriction to port 80.  If you are concerned that
> > > non-root users could launch attacks from low ports at 
> other machines,
> > > assuming that only good guys can come from low ports is 
> pretty naive.
> > >
> > > The whole business about not letting anyone but root bind 
> to low ports
> > > makes sense for a public access machine where all the first year
> > > engineering students have an account, but for a dedicated 
> application
> > > server it is kind of misdirected.  You ought to be running next to
> > > nothing but the application, and you had better trust 
> everyone that
> > > you give a login to, and you out to have the thing locked
> > > down/firewalled well.  So the tiny bit of possible 
> protection may not
> > > be worth the hassle/risks of writing your own suid-wrapper, or the
> > > complexity of having a redirect and messing with 
> site-access so that
> > > the port numbers in the zope -- what it is that parameter 
> -- base or
> > > whatever, comes out write.
> > >
> > > Just for fun - does NT have the same restriction?
> 
> Nitesh Dhanjani wrote:
> > 
> > Interesting argument. However, consider this: if you 
> completely trust your
> > 'firewalled' box, then why not run the web server as root? 
> One response,
> > in your case is the fact that you mention your trust on 
> users(humans are
> > the most easy to compromise, however that argument is a bit 
> OT). However,
> > do you trust all of your webserver code? Do you trust your cgi-bin
> > scripts and applications? And by trust I not only mean 
> harmful intent by
> > the authors of software, but unintentional bugs which can 
> be exploited,
> > and will be given the privilege to bind to <1024 ports even 
> when they run
> > as a user with least privileges.
> 
> 
> Exactly. In addition, relying solely on a firewall is a bad 
> idea from a security
> standpoint. Firewalls can. and do get breached. 
> 
> I don't run many services on _any_ of my machines for 
> security reasons. I certainly don't
> want Joe Random User to fire them up either. Consider tftpd, 
> or telnetd, or rlogin,
> rusers, rwho, ruptime, etc.. There are many ways a user can 
> compromise, not only the
> machine he is on, but other machines by having the capability 
> to bind to ports under 1024. 
> 
> Nearly all of them are off topic for this list; thus I would 
> recommend a number of the
> security resources available on the web, such as:
> 
> http://www.rootshell.com
> http://www.securityfocus.com
> 
> Just a quick example: A user can upload a custom compiled 
> version of (insert servie such
> as DNS, NIS, telnetd, httpd, etc> that uses his/her local 
> libraries, bypass /etc/services.
> since they can bind to ports under 1025, they can be started 
> by the user. Whereas, for
> example, on other systems, their app would fail. Now, 
> consider that if they used a version
> of, say ftpd, or fingerd, or named, that has known security 
> openings, they can then
> exploit this to get root accounts; the firewall being 
> bypassed by being local to the
> machine.
> 
> Remember, Cary, if you don't think like a cracker/hacker, you 
> can't stop them. If you
> can't see why allowing users (and users' programs) can be a 
> problem, doing so is an
> violaiton of the basic premise of good security:
> That which is not specifically allowed, is denied. 
> 
> And, BTW, for the record, I handle Unix/Network security for 
> a company known as
> Hewlett-Packard, so I think I have a good idea of the risks 
> and potnetial exploits ;)
> 
> 
> 
> --
> Do not meddle in the affairs of sysadmins, for they are easy to annoy,
> and have the root password.
> 
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