IDS mailing list archives

Re: ssh and ids


From: "David W. Goodrum" <dgoodrum () nfr com>
Date: Tue, 22 Jun 2004 18:31:07 -0400

Negative. The CertainT's we have deployed have 2 NIC's. The 443 traffic comes in on one NIC, and comes out the other NIC decrypted. We simply run that output into another network interface card on the NFR Sensor. We send it out the CertainT on TCP port 8091, and just tell the Sensor to monitor 8091 as HTTP. It works great.

-dave

Thierry Evangelista wrote:

David,

I've played with CertainT in the past and as far as I remember, the Radware
box is the termination point of the SSL tunnel. What Peter says is that the
IntruShield solution is able to analyse SSL flows on the fly and
*transparently* (which is a big difference, especially when it comes about
performance).
My 0.02

Thierry

-----Original Message-----
From: David W. Goodrum [mailto:dgoodrum () nfr com] Sent: mardi 22 juin 2004 19:16
To: Peter_Schawacker () NAI com
Cc: apowers () lancope com; focus-ids () securityfocus com;
mark.runion () us army mil
Subject: Re: ssh and ids


Your claim is only partially true Peter. NFR has been integrated with Radware's CertainT product for quite a while now. While it's not a single box solution, it does work very well, and the solution prices very competitively. We have a number of customers using this solution and are very happy with it.

Peter_Schawacker () NAI com wrote:

Hello Adam,

I believe you are correct to say that there are no silver bullets when it comes to detection. However, I would point out that as of the end of July, McAfee's IntruShield network IPS will offer the ability to decrypt SSL traffic (using the server's private key) and therefore to detect and prevent encrypted attacks against web servers. To date this is the first and only network IDS to offer the ability to "pierce the veil" of encryption. Note that SSL decryption is available in both IDS and IPS modes.

If anybody is interested in the specifics of how IntruShield inspects encrypted traffic there's a white paper available from http://www.nai.com/us/_tier2/products/_media/sniffer/wp_encr_th_prot.pd
f
."

Peter Schawacker, CISSP
Technical Evangelist
McAfee
Office 760 200 4258
Mobile 760 880 4258
ps () nai com


-----Original Message-----
From: Adam Powers [mailto:apowers () lancope com]
Sent: Friday, June 18, 2004 9:29 PM
To: focus-ids () securityfocus com
Cc: Runion Mark A FGA DOIM WEBMASTER(ctr)
Subject: Re: ssh and ids


There is really no one full-proof answer to this question (that I'm aware of). Encryption remains the bane of network-based intrusion detection technologies.

At the risk of speaking on behalf of such flow-based vendors as Arbor, Mazu, Q1, and (yes, my personal favorite) Lancope, I think some of the new behavioral traffic analysis technologies go a long way toward solving some of the problems presented by encryption technologies.

<light details>
By observing the duration of a "flow" (read: a TCP socket or series of related sockets) and the manner in which packets are exchanged over a "long duration" flow, a behavior-based system can pinpoint those connections that seem to be "out of the norm". During the baselining period, a behavior driven system observes connections attributes such as "duration" and "relative connectedness" to gain an understanding of the nature of the flows being created by a given network node. The flow-based, behavior-driven system should have the ability to discern between a AES gotomypc.com connection over TCP 443 and an automatic refresh connection to www.weather.com. The determination that "covert communications" are underway is done not through string matching or protocol anomaly but rather through the analysis of the flow attributes themselves (duration, packets sent/rcvd, pkt size, etc). Bottoms line: the magic is in the algorithms used to examine header traffic. Header traffic is not encrypted. </light details>

The #1 defining attribute of flow-analysis techniques is that they typically DO NOT require use of payload data to determine the presence of an attack.

As previously mentioned, there is no fool-proof plan... Flow-based technologies can be tricked... It just requires a much different science than that used by snot, sidestep, or encrypted shell shoveling.

- AP



On 6/18/04 2:18 PM, "Runion Mark A FGA DOIM WEBMASTER(ctr)" <mark.runion () us army mil> wrote:



Lets suppose the attacker is mildly sophisticated, and after making
the initial assault roots the box and installs a secure backdoor or two. Is there any IDS capable of isolating data it cannot read, except to monitor authorized port usage of a system or group of systems? Not to complicate the question, but when the attacker is using portal gates and all communications traffic is encrypted in normal channels how can an IDS participate? Monitoring normal traffic


patterns seems a bit slow for detection.

-
Mark Runion


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--
David W. Goodrum
Senior Systems Engineer
NFR Security
703.731.3765



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