Recently, I have been surprised at how little some of the application architects I interact with seem to know about the principles of authentication, and I mean, these are smart people too! When I went out to look on the internet to find some white papers I could send their way; I really found nothing of value. So, while this is in initial draft document, and I haven’t obtained any feedback from my fellow Security Architects, I am providing it here for the interested to get a better understanding of my views, as a security architect, of some of the basic principles of Authentication that I have always taken for granted.

Principles of Authentication

Defining a secure method of participant identification

Contents

Terms & Definitions    3

Participant    3

Identification    3

Authentication    3

Authorization    3

Accountability    3

Security Domain / Boundary    3

Claims    3

General Guiding Principles    4

Authentication of Participants    5

Three principles of Authentication    5

Shared Secret (Something you know)    5

Token (Something you have)    5

Unique characteristics (Something you are)    6

Authorization    6

Accountability    7

Terms & Definitions

Participant

A participant is an identity taking part in a business communication transaction. A participant may be represented by an end user, a target system, or even an entity facilitating the transmission of communication between two unique identities. A participant may have multiple identities within multiple security domains, but should be uniquely identified with a single identity within a single security domain. An example of participants may be a business user, a database, or a web service.

Identification

Identification is the method by which a participant asserts their unique identity within a security domain to another participant within that security domain.

Authentication

Authentication is the act of validating a participant based on the participant’s asserted claims or identity attributes. Authentication requires a shared secret between participants or attestation from a trusted source that asserts the integrity of the participant’s claims.

Authorization

Authorization is the act of approving access for an identity to a resource based on a successful authentication.

Accountability

The purpose of Identification, Authentication and Authorization is to maintain accountability tied to a unique identity within a single security domain, to ensure the integrity, confidentiality and availability of a system and its associated data.

Security Domain / Boundary

A security domain represents a functional environment that maintains a governed trust between participants either through shared secrets or through the use of another participant acting as an arbitrator to attest to the authenticity of participant’s claims.

Claims

A claim is a statement of fact about a participant used to assert an identity for authentication. A claim is usually a data artifact that is questionable in nature (e.g. I am who I say I am).

General Guiding Principles

1. A participant may have multiple identities, but an identity must be unique within a single security domain.

    

2. Identification, Authentication, Authorization and Accountability requirements should be dictated by the level of assurance within the system and the associated data classification.

    

3. Identities must be authenticated and appropriately authorized before obtaining access to non-public data.

    

4. Identities must be re-authenticated when crossing security boundaries.

    

    

Authentication of Participants

In order to ensure the confidentiality and integrity of business communications that contain non-public classified data, all participants within a business transaction must be authenticated before being allowed to participate within that business transaction. The foundation of authentication is based off of three primary principles where a participant asserts their claim of identity through something they know, something they have, or something they are.

Take for example, a person (participant) may walk up to the security guard of an organization (participant) and say (claim), “Hello, my name is Jack, please let me in”. While Jack has identified himself, there has been no assertion made proving his claim. The security guard may now ask Jack to enter his personal identification (PIN) code (something he knows), may ask him swipe an RFID badge or present a driver’s license (something he has), or may ask him to have his retina scanned (something he is), in order to provide access for Jack to the building.

After authenticating Jack, the security guard provides him with a badge that will attest to Jack’s authorization to be inside of the building. Jack has now crossed the security boundary of the outside world, into the organizations world. Jack as a participant, now has two identities, his identity associated with his license, and his identity associated with the badge he was provided.

In this scenario, we have identified the three principle foundations of Authentication: 1) something you know, 2) something you have, and/or 3) something you are. Additionally we have identified both direct and indirect forms of authentication, and have illustrated the principle necessity of a security boundary for appropriate authentication and authorization.

All three authentication principles, as well as the concepts of direct and indirect authentication and security boundaries are discussed within the remainder of this document.

Three principles of Authentication

Shared Secret (Something you know)

A Shared Secret is one of the foundational principles that often drives authentication. The secret represents information maintained between two participants that can be used to uniquely identify one or both of the participants within a security domain.

Within the example above, a shared secret was previously configured between the organization and Jack, such that, if Jack was able to provide that shared secret back to the organization, the organization could be reasonably sure that Jack was indeed who he claimed to be. In this scenario, as the organization was able to verify Jack’s claim directly, this was a form of direct authentication.

Token (Something you have)

A token is another form of authentication that represents a claim or a collection of claims that can be used to attest to a participant’s unique identity within a security domain. Tokenized authentication is based on a predefined trust between participants or security domains.

Within the example above, we identified multiple types of tokens that Jack may use. The first type of token was an RFID badge issued by the organization. Because the organization has a direct means to authenticate Jack based on a previously established relationship, this is another example of a direct authentication.

The second type of token discussed was Jack’s license. If the guard chose to authenticate Jack on the license he presented, the guard would be confirming Jack’s identity based on the attestation provided by a trusted third party (another participant). As the guard’s knowledge of Jack relies on the attestation of a third party, this is referred to as indirect authentication.

Within the context of our example, the security guard can use the indirect authentication method to verify Jack’s identity. As there are no current trusts established between the building security system and the license issuing authority, Jack will cross a security boundary, and this indirect authentication cannot be used to grant authorization for Jack to enter the building.

Thus, the security guard must, based on his indirect authentication, provide Jack with a set of claims that are understood within the organization itself, so Jack can be directly authenticated within the building complex. This repacking of claims from one authentication participant to another authentication participant is often referred to as Federated Authentication.

The organization may also implement another security framework in which a trust could be established between the security domains of the organization and the license issuing authority, such that Jack could authenticate to the organization’s security system directly using his license. This authentication framework is a form of pass-through authentication.

Unique characteristics (Something you are)

A unique characteristic of a participant is another form in which a participant may be identified. Unique characteristics of a user might include facial recognition, fingerprinting, voice recognition or retina scanning. Note that this form of authentication is typically used to authenticate user participants as it is arguably easier to replicate the “unique” characteristics of a non-biological entity.

Authorization

Once a participant has been uniquely identified within a security domain, the participant that is facilitating the business communication must make a decision as to whether or not an authenticated identity has been approved to operate on a secured resource. The discussion of detailed authorization requirements are outside of the scope of this document, however, future documents may be written to address authorization specifics in more detail.

Accountability

The primary goal in providing identification, authentication and authorization is to ensure accountability throughout a business system or organization. Thus, it is incumbent upon a system that has first identified, authenticated and authorized a participant to access a business resource to keep proper records of what the participant has done with their granted access. The decision of detailed accountability requirements are outside of the scope of this document, however, further documents may be written to address accountability specifics in more detail.

I started using the internet almost 20 years ago; and while I was a minor, with no job, I gained internet access in sometimes nefarious ways.  I spent my time on the internet staying out of trouble (or not getting caught), but let’s just say that I was no Angel, and my purpose for being on the internet was to learn as much as I could. 

As a result of the last 20 years of active involvement in security, I have learned to think like the criminals, and know how to attack and protect against their wily ways.  As a result, you would have a very hard time finding someone as paranoid and cautious as I am on the internet. However, this afternoon, I was a victim of Internet fraud.  Take a few minutes to listen to how I fell victim, and how I responded. 

Hopefully, the information presented here will help make you even more cautious as you fire up your browsers and go strolling down the streets of the ghetto at the midnight hour, in the pitch black.

Victims of Internet fraud often fall into two categories: those who are not paying attention (inattentive), and those who are uninformed (ignorant).  In my case, it was a combination of both.

When working on the Internet, my fingers and I have this agreement:  I think, and they type.  There really isn’t a lot of surface level communication that goes on between my fingers and brain.  I can be talking to someone about one thing, thinking about something else, and typing a third, and completely unrelated thing. 

The Inattentive phase

Sometime this afternoon while trying to deal with some online marketing things I have been doing, yelling at my boys to stop yelling at each other, and thinking through issues of regulations around export controls, I opened up my internet browser and typed in Facebook.com.  The only problem is, My fingers rebelled, ever-so-slightly, and they misplaced the E.

At the same time, as my fingers are misbehaving, somewhere out on the internet, an attacker is sitting and patiently waiting with a domain registered to a very slight variation on the name of Facebook.  This server domain name (it’s like the computers postal address) is registered in Tijuana Mexico but the traffic is forwarded to another domain registered in Panama City.  That domain is hosted on a server in the Bahamas. 

As I’m flipping through different browser windows, I come back to my “Facebook” page, and see that it is displaying a "survey" which purports (although never directly states) that it is from Facebook.  The survey, a three question survey, was filled with questions like "what do you think about social networking, do you think it brings you closer to friends, do you have any suggestions for us to make it better".  After 30 seconds, I was complete, and ready to be directed back to Facebook (or so I thought), and then the site showed a screen that said "put in your phone number to register for a giveaway".

“Eh, I suppose if Facebook wants to spend $300 out of it’s billions of dollars to give away an iPhone, my 3GS could be upgraded. Besides, what’s sensitive about my phone number, it’s on the do not call registry, and I could change it at any time for $30 dollars.”  This is what is going through my mind, as I’m continuing to yell at my boys who are yelling at each other, and at this point almost coming to blows; while I work on some marketing material and skip back from the BIS page on export controls.  After putting in the phone number, I got a text message saying "this is the code you need", and subsequently the web page prompted me to enter the code. 

“Yeah, sure, I guess”, – that’s what went through my mind.  I mean, really, what harm can come from putting in a code they just sent to my phone – there is nothing personally identifiable about that…

The Ignorance Phase

What I didn’t realize is that in the world of Cell Phones there is a whole billing infrastructure with the cell phone companies that if someone text’s you a code through the phone company, and you then give them that code which they represent to the phone companies, that equates to an electronic signature, and the phone companies then assume that you are agreeing to be billed for a specified amount (or a reoccurring specified amount).

So here I am, I have this “digital signature” in my hand, and on the next page there is a big spot to put in your code and some tiny itty bitty print – that no one ever pays attention to, right?  I typed in the code and hit submit; and the page came back and said “I’m sorry, this offer is full, would you like to see another one”?  At this point I was like “WTF!"?”.

I skimmed the page and saw the “very fine print” that said, “by entering this code you are registering for a monthly service plan for free ringtones”.  No big deal though, right; the page said that I couldn’t be entered because the deal was already full, and I should try signing up for another one.

The Response

So, I wasn’t paying attention, and I didn’t know how cell phone companies support billing services through text messaging.  But at this point, I already knew I had fallen for a scam.  So what did I do?

The first thing I did was get right on the phone to AT&T.  To hell with this company that just told me they couldn’t sign me up because they’re register was full (and I do not mean that euphemistically either) – I knew I couldn’t trust that as far as I could throw it. 

I immediately got on the phone with AT&T and had them reverse the charges and cancel the reoccurring charges.  I have an appointment with their fraud department tomorrow (they were closed today), so that I can give them as much information as possible so that they can prevent this from happening to other people.  Which leads me to my second step – I told everyone I know about it.  Sure, in the end, there might be someone who is going to say “Haha, you gots pWned” – but my response would be STFU (that’s more euphemistically).

You see, these people prey on the lack of communication; they prey on the fact that by jumping through multiple international boundaries they are all but assured they will never be pursued.  They prey on the fact that the cell phone company can just write off a couple million dollars in fraudulent charges.  And yet, the worst thing I could do is not tell everyone I know to keep an eye out, so that they too, are not victimized.

Which comes to the third and final thing I did.  I went to the Internet Crime Complaint Center (http://www.ic3.gov/default.aspx) and the FTC Complaint Center (https://www.ftccomplaintassistant.gov/) and filled out their complaint forms.  Sure, as small as this fraud attempt was, they could care less; however, perhaps these people have been defrauding individuals out of millions of dollars, perhaps every little bit of evidence they collect increases the chance that that’ll go after these guys.  But in reality, it just gave me a great feeling to tell on them!  LoL

So Remember

In the end, as a consumer surfing the internet (as you likely do – if you are reading this), keep the following in mind:

• Suspect everyone;
• Trust no one;
• Verify, verify and Verify;
• Pay attention;
• Educate yourself on the technology you use;
• Decrease the possibility that the crime lords will collect anymore money: tell everyone;
• If you think you were the victim of internet crime, act immediately!

You know, these guys are smart, they’re never going to catch them, even if they go after them.  So in the end, I just tell myself that somewhere in the world, there is an internet crime lord who is having a beer on me.  Drink it up buddy, because it’s going to be awfully hot in hell!