Hi,
I've seen some firewalls that support inspection of fragmented traffic, but
it does not mean they reassemble the traffic. This should be done at the
endpoint (host or server, or proxy).
I agree that it becomes more difficult to 'fool' firewalls or IPS/IDS with
fragmentation, but myself I had a lot of success with fragroute to bypass
IDS/IPS systems that were able to decrypt SSL traffic. Very few (not to say
none ...) were able to handle fragroute. If they already succeeded to
support IP fragmentation, they certainly messed up when using the TCP
segmentation features present in fragroute.
Regards,
----------------------------------------------------------------------------
---------------------------------
Philippe Bogaerts
mailto:xxradar@radarhack.com
http://www.radarhack.com
http://blog.securityprofessional.be/
http://www.linkedin.com/in/xxradar
NEW http://www.radarhack.com/dir/papers/Getting started with OWASP WebGoat
4.0 and SOAPUI.pdf
-----Original Message-----
From: listbounce@securityfocus.com [mailto:listbounce@securityfocus.com] On
Behalf Of Shenk, Jerry A
Sent: Wednesday, September 26, 2007 1:06 PM
To: seclt yuri; Harry Hoffman
Cc: pen-test@securityfocus.com
Subject: RE: Are Fragmentation Attacks Still Used for IDS/IPS Evasion?
Well, like almost any security vulnerability, attacks against it are
useless unless it works! There are all kinds of "old attacks" that end
up being valid attack vectors all the time. You have no idea if people
have designed the network you are testing correctly or not.
One other point here - fragmentation attacks and what can get as a
result is something that you might want to test in your lab. If you
test it in a controlled environment, you will be better able to know if
it's working and what you can expect to gain when you use it in the
field.
-----Original Message-----
From: listbounce@securityfocus.com [mailto:listbounce@securityfocus.com]
On Behalf Of seclt yuri
Sent: Tuesday, September 25, 2007 10:29 PM
To: Harry Hoffman
Cc: pen-test@securityfocus.com
Subject: Re: Are Fragmentation Attacks Still Used for IDS/IPS Evasion?
Yes but this effectively means that fragmentation
attacks are useless if launched across the 'Net and
when performing a penetration test without local
access.
Also, even internal host systems are usually
segregated from servers and server vlans by a
firewall, so even then, I can't see how fragmentation
attacks would be effective. The only scenario that I
can think of would be within the same subnet or vlan
where traffic doesn't pass through a firewall.
Please correct me if I am wrong. Thank you.
--- Harry Hoffman <hhoffman@ip-solutions.net> wrote:
yep, unfortunately not enough people using host
based firewalls and alot
of attacks happen inside of where the firewall
protects (i.e. local lan)
seclt yuri wrote:
Hi,
I was just reading up on fragmentation attacks
using
fragrouter and fragrouter as a mean of IDS/IPS
evasion. However, since almost all firewalls both
commercial and free (iptables for examples) now
have
support for fragment reassembly, are fragmentation
attacks still effective? Thanks.
________________________________________________________________________
____________
Need a vacation? Get great deals
to amazing places on Yahoo! Travel.
http://travel.yahoo.com/
------------------------------------------------------------------------
This list is sponsored by: Cenzic
Need to secure your web apps NOW?
Cenzic finds more, "real" vulnerabilities fast.
Click to try it, buy it or download a solution
FREE today!
http://www.cenzic.com/downloads
------------------------------------------------------------------------
------------------------------------------------------------------------
This list is sponsored by: Cenzic
Need to secure your web apps NOW?
Cenzic finds more, "real" vulnerabilities fast.
Click to try it, buy it or download a solution FREE
today!
http://www.cenzic.com/downloads
------------------------------------------------------------------------
________________________________________________________________________
____________
Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user
panel and lay it on us.
http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7
------------------------------------------------------------------------
This list is sponsored by: Cenzic
Need to secure your web apps NOW?
Cenzic finds more, "real" vulnerabilities fast.
Click to try it, buy it or download a solution FREE today!
http://www.cenzic.com/downloads
------------------------------------------------------------------------
**DISCLAIMER
This e-mail message and any files transmitted with it are intended for the
use of the individual or entity to which they are addressed and may contain
information that is privileged, proprietary and confidential. If you are not
the intended recipient, you may not use, copy or disclose to anyone the
message or any information contained in the message. If you have received
this communication in error, please notify the sender and delete this e-mail
message. The contents do not represent the opinion of D&E except to the
extent that it relates to their official business.
------------------------------------------------------------------------
This list is sponsored by: Cenzic
Need to secure your web apps NOW?
Cenzic finds more, "real" vulnerabilities fast.
Click to try it, buy it or download a solution FREE today!
http://www.cenzic.com/downloads
------------------------------------------------------------------------
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.488 / Virus Database: 269.13.30/1030 - Release Date: 9/25/2007
8:02 AM
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.488 / Virus Database: 269.13.30/1030 - Release Date: 9/25/2007
8:02 AM
------------------------------------------------------------------------
This list is sponsored by: Cenzic
Need to secure your web apps NOW?
Cenzic finds more, "real" vulnerabilities fast.
Click to try it, buy it or download a solution FREE today!
http://www.cenzic.com/downloads
------------------------------------------------------------------------
