Re: Auditing a firewall rulebase

[Chuck Benson <chuck () ironponies com>]

Darden, Patrick S. wrote:
> Here's my two cents:
>
> -Look for a default deny.
> -Make sure all rules are performance-based, e.g. most hit rule first in line, etc. to cut down on cpu and bandwidth.
>
> --Patrick Darden
>
>
> -----Original Message-----
> From: firewall-wizards-bounces () listserv icsalabs com
> [mailto:firewall-wizards-bounces () listserv icsalabs com]On Behalf Of
> arvind doraiswamy
> Sent: Wednesday, May 14, 2008 11:19 AM
> To: firewall-wizards () listserv icsalabs com
> Subject: [fw-wiz] Auditing a firewall rulebase
>
>
> Hey Guys,
> What parameters would you look for if you audited a large rulebase for
> an enterprise firewall? These are a few I could think of. Anything
> else that you guys consistently look at when managing/auditing your
> firewalls? Do take note that I'm talking just singularly about the
> rule-base and not other configuration information i.e: I'm not looking
> at things like -- Low console session timeout OR Telnet admin
> interface open etc. I'm looking at just the rulebase this time around.
> Here are my parameters:
>
> Rules which have "any" or an equivalent keyword in them
> Rules where an entire subnet has been granted access to a resource
> Rules where a range of IP addresses has been granted access to a resource
> Rules where a large range of ports has been opened to an IP Address / Addresses
> Rules where there are design issues in the protocol itself
>                 eg. Unencrypted traffic
> Rules which are redundant and can be removed from the rulebase
>
> Thanks
> Arvind
> _______________________________________________
> firewall-wizards mailing list
> firewall-wizards () listserv icsalabs com
> https://listserv.icsalabs.com/mailman/listinfo/firewall-wizards
> _______________________________________________
> firewall-wizards mailing list
> firewall-wizards () listserv icsalabs com
> https://listserv.icsalabs.com/mailman/listinfo/firewall-wizards
>
>   
If you can tell from logs or otherwise, look for rules that are no 
longer in use.
Look for rules that you do not have a written justification for; if a 
rule is for a single application or user group, ask if it is still 
justified.

I have eliminated a lot of deadwood with these checks over the years, 
cruft accumulates.

Chuck Benson

_______________________________________________
firewall-wizards mailing list
firewall-wizards () listserv icsalabs com
https://listserv.icsalabs.com/mailman/listinfo/firewall-wizards