Re: Log checking?

[Kevin <KKadow () gmail com>]

On Thu, 30 Sep 2004 20:35:14 -0500, FW Wizards Mailing List
<fw-wizards () danschmitz com> wrote:
> While I've really enjoyed reading this communication regarding logging,
> I'm a little concerned.  I think that all incoming traffic that is
> dropped should be logged.  An accept for an incoming ftp request would
> look legitimate, when logging drops would show that an attempt on a
> blocked port took place prior to that "legitimate" ftp traffic.
> Additionally, for legal purposes it would be important to have
> documentation of all drops that a firewall had from a specific
> destination.  I don't think there is ever too much "noise."  You need to
> filter your logs to provide you with the information you need.  I do
> agree that it is vital to monitor your employee's behavior.  The only
> traffic that I wouldn't want to log is NetBIOS traffic, etc, being
> dropped by the internal interface on the firewall.  A proper IDS
> configuration (one on the inside and one on the outside) will help you
> to audit your security policy.  Without proper logging, how can your
> security policy be as effective as it could be?  Personally, I'm all for
> logs that will provide the information desired upon need.  I'd hate not
> to get enough information when it is needed from a firewall.

This depends greatly on the scale of your infrastructure -- My
outbound firewall logs for permitted traffic exceed six gigabytes per
day.

As of last week, 75% of the lines logged by by inbound firewall events
were worm traffic on the standard microsoft file sharing ports.

As of this week, we have added simple deny ACLs on the inbound edge
routers to silently drop traffic towards these ports, so I can once
again run a full day's worth of logs through my Perl analysis scripts
without thrashing swap due to running out of RAM.


KevinK
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