RE: [Full-Disclosure] Comcast using IPS to protect the Internet f rom their home user clients?

[Chmielarski TOM-ATC090 <Tom.Chmielarski@xxxxxxxxxxxx>]

Yes, they say they are now doing this.
http://www.infoworld.com/article/04/03/09/HNcomcastspam_1.html
-Tom
-----Original Message-----
From: full-disclosure-admin@xxxxxxxxxxxxxxxx 
[mailto:full-disclosure-admin@xxxxxxxxxxxxxxxx] On Behalf Of Frank Knobbe
Sent: Monday, March 08, 2004 8:29 PM
To: full-disclosure@xxxxxxxxxxxxxxxx
Subject: [Full-Disclosure] Comcast using IPS to protect the Internet from their 
home user clients?


This post should probably have gone to SF-PenTests, but since it is more of a 
discussion item, I thought about Full Disclosure, the list for vuln info and 
everything else :)


Anyhow, I noticed that certain vulnerability scans, for example scans using 
Nikto and similar tools, when run from a Comcast address show a different 
behavior than when they are run from a clear, uncontrolled Internet connection 
(i.e. corporate T-3). In fact, it appears like Comcast has an Inline-IDS (some 
call it an IPS ;) sitting on its wires, filtering out certain signatures and 
blocking subsequent access for a short period of time. For example, scan 
progresses, then hangs inexplicably, then resumes, trips a sig, and hangs 
again. At the same time, the same scan from a non-Comcast address continues 
without any hick-ups. Targets have been ruled out (up and running, verified at 
the same time from different addresses), and connectivity to the rest of the 
net remains. It's looks like just the src-dst address pair is used so that all 
connections from a Comcast src to that particular dst are blocked for a short 
moment (1-5 minutes).

Has anyone else noticed that? Is Comcast actually attempting to keep all those 
worms'n'viruses of their clients away from the Internet?

How many other ISP's are known to use IPS's inline to protect themselves from 
the 'Net, or protect the 'Net from themselves?

Regards,
Frank (routing all scans via VPN through corporate hosts ;)





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