Firewall Wizards mailing list archives

Re: Firewall Audit Programme/checklist


From: Chad Schieken <cschieke () advsys com>
Date: Mon, 16 Mar 1998 16:23:46 -0500


Agreed, a detailed checklist, broken down in true/false  (yes/no) type 
questions and answers would be almost impossible to build (completely) and out
of date the second you typed it into your text editor.

However a specialized framework to tackle this problem seems inorder. This would
allow the analysis to be done by the competent individual, but the investigation
to be accomplish be a jr. or less knowledgable individual. 

further it would help even the most knowledgeable guru stay on-track and not
miss details or leave portions out. 

It could be validated based firewall/gateway type and product sets. And 
slightly or not so slightly modified for differnent types of configuration, 
levels of protection, and archcitectures.

Now the interesting part, authoring such a framework, would take some time, need
constant updating, and almost always need improvement. but that oould be better
than nothing. 



Has anyone found or got an Audit Program for firewalls? or an audit
checklist for firewalls?

I do a lot of training for a "big six" firm and an audit checklist
is a fairly common request. I haven't ever given one to anyone,
because I don't have one. If you know what you're doing when you
audit a firewall, you don't need a checklist. If you don't know
what you're doing, you do -- but then you shouldn't be taking
someone's money to audit their firewall.

There's one book out called "Practical IT Security Auditing" or
"Systems IT Auditing" by Barton Neal. It includes checklists that
are semi useful, BUT the problem, once again, is that it doesn't
include what the checklists *MEAN* which is the information that
the auditor really needs. Also, like many audit checklists, it
is too hidebound and regulated. The firewall auditing section, for
example, appears to assume that you're auditing a firewall toolkit
based firewall (!)

i.e.:
-----
...Ensure that the application gateway firewalls' host operating
system (usually UNIX) has been properly modified to disable services
that could be used to subvert the security of the firewall software
program:
      1) Review the /etc/inetd.conf file and the /etc/rc start-up
      files to ensure that all standard network services have been
      disabled by commenting out (#) their entries
...

Now, obviously, that's not going to make a lot of sense on a
Checkpoint, or a Firewall/Plus, etc. Someone who was using this
checklist would either look stupid or would have to know enough
about what they're doing to not need it in the first place. :)

It's a tough problem, because there's a methodology but it's really
pure systems analysis. You need to start at zero and build facts
about the firewall, then understand the significance of those facts
in the installed context. It takes a lot of expertise -- more than
can be comfortably fit in a book or taught. Even if you did fit it
on a checklist or in a book by the time you had it written down
the rules would have changed. :(

The big problem is that IT audit comes from a mainframe background.
Mainframes are *simple* to audit. You just have to make sure
that RACF is configured right and that the SNADS are connected
to the DASD by a JCL or whatever. Out on the Internet, the products
mutate overnight, there are dedicated single process systems
that break a lot of rules, and there are lots of applications
that are basically undocumented. :( What you really want isn't a
checklist, it's a flow-chart. A really BIG flow-chart that goes
kind of like:

if you're looking at a firewall
      look at the policy for incoming traffic
              does it allow http in?
                      to what machine?
                              what OS is it running?
                              are the CGI scripts audited?
                              is the httpd up to date?
              does it allow smtp in?
                      to what machine?
                              what OS is it running?
                                      if UNIX
                                              is sendmail up to date?
                                      else
                                              WTF?
              does it allow other services in?
                      what service?
                              WTF?

The problem is that the *INTERESTING* stuff is the "WTF" entries
and those are also the danger points. :(

I'm not trying to attack you for answering a simple and straightforward
question. But, I beg you, if you find a checklist, please don't think
it's something you can apply in a simple and straightforward manner.

mjr.
--
Marcus J. Ranum, CEO, Network Flight Recorder, Inc.
work - http://www.nfr.net
home - http://www.clark.net/pub/mjr




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