RE: Multi-Factor Authentication Concern

["Uber Wannabe" <nucleargeekdown () gmail com>]

Is it not enough that everything you read (including the Wikipedia page)
about multi-factor authentication refers to "the user" or "the originator"?


The purpose of multi-factor authentication is to authenticate a single user
through multiple authentication methods.  Same with two-factor
authentication.

Authenticating multiple users based on differing, or even similar,
authentication criteria to secure something valuable is not multi-factor
authentication.  There are multiple authentication methods, but they are not
authenticating a single user.  Furthermore, if it was multi-factor
authentication, then every user would have to authenticate using ALL OF THE
SAME implemented authentication methods, not using only some.

The practice of having multiple users authenticate to satisfy security
requirements would have to come under another term and, as far as the
argument is concerned, this other term really does not matter.  Logic,
reasoning, and reading the specifics of multi-factor authentication will
suffice here.


-- N/A


-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com] On
Behalf Of Justin Ross
Sent: Tuesday, August 14, 2007 1:17 PM
To: Jason Sewell; security-basics () securityfocus com
Subject: RE: Multi-Factor Authentication Concern

I'm sorry, I have to play devil's advocate and disagree.

Initially I wanted to agree that Multi-factor authentication did indeed
refer to the same person; However, I do not believe it to be the case
after I too, took it to the most basic level, reading the actual
definition of the words, which I included below as well as the
dictionary referred to. 

I do not believe Multi-factor Authentication necessarily refers to a
single user, nor even a living entity. For example, if multiple
handwriting experts, and a computer with handwriting analysis algorithm,
and a tarot card reader, as well random people on the street, all
confirmed the authenticity of a signed document by Abraham Lincoln,
would that not be Multiple-factor Authentication of that document? 

Why do nuclear submarines require multiple people with keys and codes to
press the launch button, and approval from the president? Is that not
Multi-factor authentication of not even individuals (who also pass
authentication checks to even get on the submarine) but a process (or
even multiple processes such as chain of command as well)? When you say
"as it is commonly defined", please cite where you are getting the
definition from? Isn't the point of this thread that you cannot cite one
and need help locating such a source? If you said "culturally defined by
the INFOSEC community", I would somewhat agree.

Really though, I think the answer hinges on the definition of the words
themselves, which doesn't necessarily indicate a person is involved (at
any point), let alone the single "same" person.

Just my 0.02.

Justin.Ross
Security Engineer


American Heritage Stedman's Medical Dictionary  
multi-
Many; much; multiple: multiarticular. 
More than one: multiparous. 
More than two: multipolar.


American Heritage Dictionary 
fac*tor     
One who acts for someone else; an agent. 
A person or firm that accepts accounts receivable as security for
short-term loans. 
Mathematics One of two or more quantities that divides a given quantity
without a remainder. For example, 2 and 3 are factors of 6; a and b are
factors of ab. 
A quantity by which a stated quantity is multiplied or divided, so as to
indicate an increase or decrease in a measurement: The rate increased by
a factor of ten.  


American Heritage Dictionary 
au*then*ti*cate 
To establish the authenticity of; prove genuine




-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Jason Sewell
Sent: Tuesday, August 14, 2007 7:05 AM
To: security-basics () securityfocus com
Subject: Re: Multi-Factor Authentication Concern

I appreciate all of these responses.

The general consensus seems to be:

1) The system that "Bob" has implemented does not reflect multi- factor
authentication as it is commonly defined, and
2) there may be some esoteric reason to require different people to
provide different authentication factors to protect a single resource,
but
3) such a convoluted access control mechanism is not appropriate for
protection of our data center, and furthermore
4) accounting and logging are complicated by such a system.

However, what I still have not found yet is an authoritative document
that I can point to and say "Bob, you're wrong". He's a hard-headed guy
and responses from security experts on a mailing list won't convince
him. I looked at all of the suggested links, including the Wikipedia
article, and I cannot find anything that explicitly states that the
factors in a multi-factor authentication system must all be from the
same person.

So, I'll show him these response, and I'll continue to try to find an
authoritative source for my assertion (or perhaps I'll edit the
wikipedia article).

Thanks again everyone for you help!


On Aug 14, 2007, at 8:58 AM, Kevin Wilcox wrote:

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> Mngadi, Simphiwe (SS) wrote:
>
> > All three are accountable; I don't see the logic in your hypothesis. 
> > in anyway authentication should be monitored, and your concern should

> > have been build-in into the security system.
>
> All three *are* accountable and therein lies the problem - only
> *one* of
> the individuals actually entered the data centre but it appears as if 
> all three of them entered. Authentication is not only a method for 
> authorization, it is a method of accounting for who accessed what 
> resources. Just because all three of them are authorized to be in the 
> data centre doesn't mean that any one of them should be able to gain 
> entry using the credentials of the other two. One of the things 
> multi-factor authentication attempts to address is the scenario where 
> an individual can pass themselves off as someone else - basically ID 
> theft.
>
> Another scenario would be on-line banking. Suppose you and your 
> business partner have access to the same account. You decide to use 
> web-based banking. To access the account information you have to login

> using a password then enter a PIN. To gain access to the account 
> details you would not login using your password then enter your 
> partner's PIN - you would use *your* password and *your* PIN. Like the

> data centre scenario, just because more than one person has access to 
> a resource doesn't mean you allow authentication credentials from 
> anyone with access - it destroys the concept of accountability. 
> Instead you require that all of the authentication credentials come 
> from the same person so you know who to hold accountable if something 
> happens (and because it could be the law in your vicinity).
>
> That said, there *are* times when group level access may be desired 
> and a "piece of the key" from each person is acceptable (or required) 
> - if that is the case then the original question is moot.
>
> I hate relying on hypothetical examples but it really does come down 
> to "what are you trying to accomplish with your authentication 
> methods?"
> and "what are the laws in your area?". If group accountability is your

> goal then you can suffice with allowing credentials from anyone at any

> stage in the process (just make sure you have other accountability 
> measures in place). If you want granular accountability at the 
> individual level then all of the credentials must come from the same 
> individual.
>
> I hope that helps.
>
> kmw
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