RE: Concepts: Security and Obscurity

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

Passwords add a level of security - I agree with this - how much is
debateable and needs to be set to the levels of required protection.

I would have to know more of the authentication method to answer your
question: " In this particularly scenario, does this layer (which is not
STO) enhance the security of the server software?". A Simple answer is
that it may, but the mechanisim would need to be assessed. 

Adding IPSec or even SSL tunneling to get to the protocol would add
value, other controls may or may not and several proposed authentication
schemes have "issues". 

Craig



Craig Wright
Manager of Information Systems

Direct +61 2 9286 5497
Craig.Wright () bdo com au

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

From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Michael Rash
Sent: Wednesday, 18 April 2007 11:13 AM
To: security-basics () securityfocus com
Subject: Re: Concepts: Security and Obscurity

On Apr 18, 2007, Craig Wright wrote:

> > From Wiki:
> security through obscurity (sometimes security by obscurity) is a
controversial principle in security engineering, which attempts to use
secrecy (of design, implementation, etc.) to provide security. A system
relying on security through obscurity may have theoretical or actual
security vulnerabilities, but its owners or designers believe that the
flaws are not known, and that attackers are unlikely to find them.
>  
> Costas Tavernarakis
> Security Through Obscurity (STO) is the belief that a system of any
sort can be secure so long as nobody outside of its implementation group
is allowed to find out anything about its internal mechanisms. Hiding
account passwords in binary files or scripts with the presumption that
"nobody will ever find it" is a prime case of STO.
>  
> Jay Beale, Lead Developer, Bastille Linux Project has a definition,
Schiener defines it and  Kerckhoffs' doctrine - 1883 all define it.
>  
> Passwords have their issues - but they are not a obscurity factor.

Yes, passwords have their issues, but (keeping the level of abstraction
high) I'll assume your statement above indicates that you agree that
passwords help security.

I'm sure you will also extend this then to encryption algorithms (which
also have their problems of course, but that is not important for this
discussion yet).  So, encryption algorithms do not suffer from security
through obscurity.

I'm not so interested in whether STO helps or hurts security; as we can
all see this is controversial.  Regardless of the answer to this, what
I think is more useful is to determine whether a particular security
measure can be classified as STO.

In the context of wireless protocols, running servers on different
ports, port knocking, SPA, and other things discussed in this thread,
suppose that piece of server software contains a remotely exploitable
vulnerability in a particular function.  Further, suppose that this
function can be interacted with by a client before any credentials are
supplied.

Now, suppose that I place an additional authentication layer in front of
this vulnerable function that depends on a password and an encryption
algorithm (speaking generally) which I think we agree do not suffer from
STO.  With this layer, any client cannot interact with the vulnerable
function without supplying the required credential.

In this particularly scenario, does this layer (which is not STO)
enhance the security of the server software?

--
Michael Rash
http://www.cipherdyne.org/
Key fingerprint = 53EA 13EA 472E 3771 894F  AC69 95D8 5D6B A742 839F




> From: listbounce () securityfocus com on behalf of Michael Rash
> Sent: Tue 17/04/2007 2:05 PM
> To: security-basics () securityfocus com
> Subject: Re: Concepts: Security and Obscurity
>
>
>
> On Apr 17, 2007, Craig Wright wrote:
>
> > 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.
>
> I think part of the confusion surrounding this whole discussion is
that
> I'm not sure we all agree on a good definition for what "obscurity"
> means in the context of computer security.  If we can agree on a
> definition, then I think we could start to test the statement above.
>
> If one accepts the dictionary definition of "obscurity" as "the
> condition of being unknown", then the term could be applied to an
awful
> lot of things in the computer security world.
>
> Would you argue that passwords (taken generally) add an important
> measure of security to various software?  If so, then why do they not
> qualify as something in "the condition of being unknown"?
>
> --
> Michael Rash
> http://www.cipherdyne.org/
> Key fingerprint = 53EA 13EA 472E 3771 894F  AC69 95D8 5D6B A742 839F
>
>
> > 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
> >
> > Direct +61 2 9286 5497
> > Craig.Wright () bdo com au
> >
> > BDO Kendalls (NSW)
> > Level 19, 2 Market Street Sydney NSW 2000
> > GPO Box 2551 Sydney NSW 2001
> > Fax +61 2 9993 9497
> > www.bdo.com.au
> >
> > Liability limited by a scheme approved under Professional Standards
Legislation in respect of matters arising within those States and
Territories of Australia where such legislation exists.
> > The information in this email and any attachments is confidential.
If you are not the named addressee you must not read, print, copy,
distribute, or use in any way this transmission or any information it
contains.  If you have received this message in error, please notify the
sender by return email, destroy all copies and delete it from your
system.
> > Any views expressed in this message are those of the individual
sender and not necessarily endorsed by BDO Kendalls.  You may not rely
on this message as advice unless subsequently confirmed by fax or letter
signed by a Partner or Director of BDO Kendalls.  It is your
responsibility to scan this communication and any files attached for
computer viruses and other defects.  BDO Kendalls does not accept
liability for any loss or damage however caused which may result from
this communication or any files attached.  A full version of the BDO
Kendalls disclaimer, and our Privacy statement, can be found on the BDO
Kendalls website at http://www.bdo.com.au or by emailing
administrator () bdo com au.
> > BDO Kendalls is a national association of separate partnerships and
entities.
> > -----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