RE: Skype

From: Jason M. Beauford (jbeauford@subropartners.com)
Date: Thu Dec 27 2007 - 13:26:21 EST


Look at the Skype website for details on ports:
http://www.skype.com/help/guides/firewalls/technical.html

Default Deny Egress traffic should block all traffic except that which
is explicitly allowed. Good rule but sometimes difficult to get going,
in the beginning.

I've used Websense with PIX integration and it effectively blocked Skype
traffic. I've also used MS Group Policy to deny access to skype.exe on
all systems, but this is easily circumvented should the user rename the
executable. However, my users do not have rights to install software or
to modify anything below the %PROGRAMFILES% dir. Again this is
circumvented should they bring it in on a USB key, but if you lock down
USB access as well, they wont be able to initialize the drive.

jmb

-----Original Message-----
From: Misiu [mailto:Misiu_@gmx.de]
Sent: Wednesday, December 26, 2007 6:15 PM
To: Nikolaj; pen-test@securityfocus.com
Subject: Re: Skype

> Any ideas how to profile skype traffic and possibly block it? I've
> heard rumors that cisco content switch can detect skype traffic and
> block in 90% of the cases? Any ideas on this topic and general skype
> security risks for the corporate environment?

Hello,

I read recently about blocking skype. BlueSocket Proxy Applyance
http://bluecoat.com/ can do it and CheckPoint Interspect
http://www.checkpoint.com/products/interspect/.
And there are some others but I don't remember the names.

Laters,

misiu

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