Firewall Audit

[paul at pauldotcom.com (Paul Asadoorian)]

Agreed, auditing firewalls is a two-phased approach (Even three).
First, you need to understand your rules and audit them on a regular
basis.  Of course, change management people HATE this because I would
put in a change notice every couple of months and call it "maintenance"
and clean-up the firewall rules, remove rules that didn't exist, etc...

Second, you should perform scans through the firewall and make sure its
blocking what it says it should be blocking.

Third, you should audit your firewall logs, they can also tell you if
you made an "oops" and are allowing traffic that you should not.  I
actually had a systems administrator catch a firewall rule that was
incorrect because they were seeing FTP login attempts from the Internet!

Cheers,
Paul

Ron Gula wrote:
> On 6/9/2009 3:45 PM, Chris wrote:
> > Hi all,
> >
> > I have been asked by management to conduct an audit of a Firewall,  no
> > actual specification has been created.
> >
> > So what I?m asking is, I have to create a terms of reference and
> > specify what I?m going to audit.
> >
> > I have started looking at the OSSTMM Firewall test, and would like to
> > know how to conduct the test.
> >
> > Tools(nmap,hping,nessus) and what types of things I should be looking
> > for in the scans.
> >
> >  
> >
> > */Help me, /Pauldotcom//; /you/'/re my only hope/*/ (Sorry big
> > StarWars fan)///
> Tools aside, I'd start with the config of the firewall and attempt to
> understand how it is
> set up. If there is no real policy for which to compare this against,
> I'd audit what can get
> through in both directions and then describe this to your management.
> I'd also do a vuln
> audit of the firewall, but this should be a detail and not where you start.
>
> Ron Gula
> Tenable Network Security
>
>
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-- 
Paul Asadoorian
PaulDotCom Enterprises
Web: http://pauldotcom.com
Phone: 401.829.9552