"Events that led to an intrusion". That doesn't necessarily imply full
session logging. For example, NFR can log the existence of all sessions
on the network, which is considerably smaller than the actual session.
A sample record looks like this (except normally in tabled format):
Time: 30-Aug-2004 09:35:12
NFR: home-nid
Start Time (in seconds since the epoch):1093872886
Source Address: 10.0.1.215
Source Port: 2106
Destination Address:65.202.219.131 (support.nfr.com)
Destination Port: 443
Total Bytes: 18534
Client Bytes: 5002
Server Bytes: 13532
Most Network IDS vendors will have some form of "General recording" such
as this.
This can be very useful in determine what an attacker did leading up to
an attack. It won't get you the raw materials though. If you flat need
all the raw data, I'd recomend tcpdump. But, like I said, tcpdump can
be a lot of information on a fast network. I hope you buy a big hard drive.
Raj Malhotra wrote:
Hi
we definitely agree with david's and your observation that session
logging is not the goal of an IDS. But we would like to know the
events that led to a successful intrusion and not just whether an
intrusion took place or not. We will not be able to formulate better
policies if we are unaware of the sequence of events that leed to an
intrusion.
could you please suggest some tools for session logging?
thanks
----- Original Message -----
From: Vijayakumar.S <vijay@nsecure.net>
Date: Tue, 31 Aug 2004 10:07:18 +0530
Subject: Re: session logging IDS
To: "David W. Goodrum" <dgoodrum@nfr.com>, Raj Malhotra <ral.mal@gmail.com>
Cc: focus-ids@securityfocus.com
Yes, I agree with David.
The purpose here is to detect and prevent the intrusion, that most of
the IDSs do. There are lots of tools available to do the session
logging.
Raj, if you are in the phase of testing the IDS/IPS you can test
various other functionalities which are offered by various products
currently in the market.
----- Original Message -----
From: David W. Goodrum
To: Raj Malhotra
Cc: focus-ids@securityfocus.com
Sent: Tuesday, August 31, 2004 3:34 AM
Subject: Re: session logging IDS
Hmmmm, I would like verification that either Cisco or Intrushield (or
any other IDS/IPS) can actually capture an entire session from beginning
to end, when the alert was triggered somewhere in the middle, and that
they can do it all the time. Most Network IDS & IPS systems can capture
the offending packet. Many can capture the offending packet, PLUS the
rest of the session (which is what we at NFR do). I haven't seen any
that can guarantee capturing the entire session from beginning to end,
unless they were capturing EVERY session (regardless of whether
something bad happened in that session). Here's an example:
I login via ftp. I stay logged in for 10 minutes, browsing around,
downloading some large benign files, but doing nothing bad. Then, I try
to get /etc/password. Boom I trigger an alert. 10 minutes of packets
are long gone... potentially many, MANY MegaBytes of data have passed
during a single session. On a gigabit network, 10 minutes is an
EXTREMELY long time. Unless your IDS or IPS is recording EVERY SINGLE
packet for great lengths of time, to a hard disk somewhere, it will be
all but impossible to go back in time and recreate the full session from
beginning to end. Starting recording from triggertime is easy, and I
believe a lot of IDS and IPS systems do this.
Having said that, it IS possible to use some third party utility to do
something similar to what you want, but even then there's still no
guarantee: TCP sessions can stay open for hours and hours if necessary.
For example, I can setup a box to do nothing but run tcpdump on the same
wire I am doing IDS/IPS on, with a huge hard drive. Let's say a 128GB
drive. If I'm monitoring a fully saturated 100Mbps, I will fill up that
hard drive in just under 3 hours. I can easily keep a session open for
3 hours before doing something... "bad". Plus, as network speeds
increase, you will not be able to write your raw network data to that
hard drive fast enough (or read it fast enough if alert rates are high.
-dave
David W. Goodrum
Senior Systems Engineer
NFR Security, Intrusion Detection & Prevention
http://www.nfr.com
Raj Malhotra wrote:
Hello all,
We are evaluating available NIDS products which would work at 100 mbps
and would also do "session logging". By "session logging", we would
want the IDS to log the "entire session" and not just the session
"after" an intrusion is detected.
We saw a couple of IDS which would probably be able to do something like this,
Cisco IDS
Intrushield
Cisco offers session logging as well as replay.
Intrushield says something like "Highly customized capture of
individual packet, individual session, specific source/destination, or
entire traffic stream upon attack detection" which might be translated
as "logging of the session only after an attack has been detected".
Can anyone tell us more about these or any such IDS that are available
which can log the entire session.
Also, has anyone used any of these and with what degree of success?
You can mail us back off the list if you so wish so.
thanks
Raj
--
David W. Goodrum
Senior Systems Engineer
NFR Security
703.731.3765
