Monday, June 2, 2014

Looking at the Microsoft Store's Authentication

A few days ago I called the Microsoft Store about an order I had placed online. After discussing what I wanted to change, the operator explained that before she could make any updates to my account she needed to check my email address (up until this point, I had only told her my name and my order number) and that she would be sending a code to that address. After confirming my email address, I quickly signed in to my account, read the code back to her and from that moment on I was verified--it was as simple as that. Let’s break this down from a security perspective.

The traditional route of authentication during a telephone call is to ask a series of questions that only you “should” know the answers to. The problem is that this isn’t always the case and these answers are generally easily discoverable: Google can help with answering what year someone got married in or what their maiden name was; if you’re OK with a little more work, you could examine the public records or even just ask the individual—I doubt most people will have a problem telling you the name of their first pet if brought up unsuspiciously in conversation.


Using a verification code bypasses all of this and places the burden of authentication solely on you having access to the email account that is registered with the Microsoft Store. The assumption is that you know the password to access your email account / that you have access to your email account. Reading the verification code back is evidence of this and satisfies that you are who you claim to be.


This becomes really interesting if the operator has no access to the code and cannot proceed without it as it presents the situation, that as well as providing authentication of you, can also provide authorization for the operator. Without the code, they would be considered unauthorized and would not be able to update an account unless they were supplied the code. This works great in preventing the operator from being coerced into updating the account, as without the code, they really have no way to do this.


I’m impressed with the ease of using a verification code sent by email and the potential it has for offering both authentication and authorization. Of course, if I was unable to access my email account at the time I called, I might have a less favorable opinion; however, an easy alternative would have been to send the code to the mobile phone that was on my account.

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