RE: Re: Concepts: Security and Obscurity

["Craig Wright" <Craig.Wright () bdo com au>]

Hello Justin,
In some cases it may aid, but there is still a cost of implementing
this. My argument is that there is no significant quantifiable gain to
security through the implementation of a layer of obscurity. 

This is a valid hypothesis in the support of a proposition that security
is improved somewhat through obscurity, though I still fail to see the
proof of this. It would make a good experiment however.

I do not believe that the survival of a system would be significantly
impacted through this type of change. Many ports advertise themselves
(esp. the public ones) and it is limited to services that are in
themselves a "secret". For instance, it would not be feasible to place
an internet SMTP server on TCP 10,025. You would not get any mail.

In the case of a SSH protocol I do not see that the prevalence of
threats from worms is significant enough to impact the survival time of
the host. 

Regards,
Craig



Craig Wright
Manager of Information Systems

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Craig.Wright () bdo com au

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-----Original Message-----

From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Justin Lintz
Sent: Tuesday, 17 April 2007 10:55 AM
To: security-basics () securityfocus com
Subject: Re: Re: Concepts: Security and Obscurity

I am jumping in late on this and don't know if this was brought up
already so I apologize in advanced if it has... but what about worms
and that are set to scan networks looking for services on specific
ports?  If you change the default port for a service, that alone could
save your machine from being compromised in a 0-day exploit from a
worm that only checks for the service on the default port.

- Justin Lintz