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Re: Inet security



Andrew Sackville-West wrote in Article
<20070614180510.GA16458@localhost.localdomain> posted to
gmane.linux.debian.user:

> On Wed, Jun 13, 2007 at 11:08:39PM -0700, Mike McClain wrote:
>> I saw this on usenet and wonder about the validity of this statement.
>> 
>> 'Seriously any system is as secure as the services you export, if you
>> have nothing listening that can do you harm you are secure...'
>> 
>> Disregarding email exploits and exploits through your browser is this
>> true? Assume the hardware is inviolate.
>> Thoughts?
> 
> a port with a listening service is like a locked door with a doorman
> inside waiting to open it for whoever knocks. If they know the
> codeword he'll open it for them.

That's how port-knocking[1] works.

> So the service (as the doorman) determines how serious the security risk 
> is at the port (door). 

Well, in theory, yes.  The problem with this formula is that some services
are promiscuous and don't care who they serve to (http, finger, gopher,
etc).

> If there is no service listening at the port, then there is no way to open 
> that port.  

Outbound connections require ports, too!

> Of course, since you are running Debian, there are no windows for
> things to climb through and open the door from the inside. ;)

Don't say things like that.  What you just said there is like a Windows user
saying, "Why should I stay patched and run antivirus software?  It's not
like I use this computer for anything serious..."

-- 
Paul Johnson
Email and IM (XMPP & Google Talk): baloo@ursine.ca




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