A Guide to Multi-Factor Authentication

Created on Apr 21 2016, 12:11 AM by Darla Scott

Today, computers and smart devices are inexpensive enough that we can own many of them: smart phones, laptops, tablets, and even wearable micro devices. Our work and private lives demand portability. This, along with a trend towards moving enterprise servers into the cloud, makes secure user authentication even more imperative…and tricky. That brings us to multi-factor authentication (MFA), what it means, and how it is achieved.

What Is Multi-Factor Authentication?

The goal of multi-factor authentication is to create a layered defense of two or more independent credentials: what you know (password), what you have (security token), and what you are (biometric verification). Requiring multiple factors to authenticate a user makes it more difficult for an unauthorized person to gain access to computers, mobile devices, physical locations, networks, or databases; each successive layer should help protect where other layers may be weak.

Multi-factor authentication is becoming more common, particularly in the financial industry, and is advancing to include retina and fingerprint scanning, voice recognition, and even facial recognition.


How Does Multi-Factor Authentication Add Security Benefits?

If only it were possible to develop a single method of authentication that was 100 percent accurate and could not be hacked—we wouldn’t need multi-factor authentication. But passwords can be seen, overheard, guessed, or bypassed; a token can be lost or stolen; and an identical twin or using a photograph may even work to fool biological recognition systems. This is why multi-factor authentication is currently very important to account security.

The concept of security using multi-factor authentication is that, while there may be a weakness in one authentication factor—say, a stolen password or PIN—the strength of a second or third factor would compensate to provide proper authorization for access.

What Multi-Factor Authentication Options Are Available for Mobile Devices?

One-time passwords

Applications are available which generate one-time passwords in the same way that security tokens have operated in the past. The one-time password is generated and sent to the mobile device using a time-based SMS.

Using a smartphone or tablet eliminates the need for a user to keep track of a token, and companies incur less cost replacing lost tokens, activating tokens for new employees, or deactivating tokens when an employee leaves.

Biometric authentication

Top smartphone manufacturers understand that security is a growing customer concern, and have also started offering biometric authentication to ensure that only the authorized user can access the device. Each of these techniques have advantages and disadvantages.

Biometric Verification



Fingerprint authentication Individuals have unique fingerprints Requires integration with network access software
Voice recognition No extra hardware is necessary Not effective in settings where the user must remain quiet, or with excessive background noise
Facial recognition or retinal scanning No extra hardware is necessary (when the device is equipped with a camaera) Not effective in low light, and possible to defeat authentication with a photograph

How Is Multi-Factor Authentication Implemented in the Cloud?

As data, communication, training, storage, server infrastructure and more are migrated to the cloud, IT admins must deal with the risks of moving beyond the more traditional on-premises server location. Multifactor, random authentication for user access is essential to protect data in the cloud.

Microsoft, Google, Amazon Web Services, Facebook, and Twitter—among others—all offer two-factor authentication for access to their cloud services, and some are extending to multi-factor authentication strategies.

Multi-factor authentication for Office 365

Office 365 requires a password to access applications on PCs, Macs, and mobile devices. The Office 365 admin tool automatically issues a random, 16-character token for users to sign in. When signed in, users are prompted to set up additional authentication.

  • Call My Mobile Phone: When the users receive the confirmation call, they press # in the phone's dial pad to log in.
  • Call My Office Phone: This works like Call My Mobile Phone, but the confirmation call is sent to a separate line, such as a desk phone.
  • Text Code to My Mobile Phone: A code is sent via SMS text message to the user’s phone, to be entered into the Office 365 login form.
  • Notify Me through App: The user can use a Microsoft smartphone app to receive and confirm the notification; the app is available for Windows Phone, iPhone, and Android.
  • Show One-Time Code in App: This uses the same app as for the Notify Me through App option, but sends a one-time, six-digit code that must be entered in the Office 365 login screen.

Multi-factor authentication for Office 365 using Microsoft Azure Active Directory

Office 365 with Microsoft Azure Active Directory is an enterprise-level solution that requires users to correctly enter a password, and then acknowledge a phone call, text message, or an app notification on their smartphone to authenticate and sign in.


What Is the Best Way to Implement Multi-Factor Authentication?

Using and supporting multi-factor tools requires that IT organizations coordinate and configure the enterprise infrastructure to get protected logins working properly. Most tools include various software agents that can protect VPNs, SharePoint servers, Outlook Web App, and database servers. As more traditional hardware-based onsite servers move into the cloud, most multi-factor solution vendors offer cloud and on-premise options. Customers are choosing offsite deployments more and more because of the support and management flexibility the cloud offers.

It’s important to evaluate multi-factor authentication products carefully to determine how each one differs subtly with regard to the desired deployment. Not every vendor can handle all scenarios equally well, and this is often a prime factor in product selection. Here are a few questions to ask when preparing to look more closely at multi-factor authentication products for a business:

  1. How much private information does the network handle? If the network currently doesn’t handle much private information, or plan to expand the storage of critical data, it’s probably not necessary to change existing authentication methods.
  2. Who will need to view the reports produced by these products? It’s important to determine who will receive alerts when something goes wrong with the authentication system. Some products can send out alerts whenever anything goes wrong, and most enterprises don't want to get management into a fire drill unnecessarily. 
  3. Does the business require the ability to scale up deployment? It’s important to consider future licensing costs. Most multi-factor products are used to handling tens of thousands of tokens and users, but they can also serve a smaller enterprise.
  4. Who will be among the initial collection of pilot users? This might determine which direction a company takes for securing particular apps and use cases.
  5. Are employees already using the two-factor authentication tools available with some consumer services? If not, enterprises should start spreading the word and making employees familiar with second-factor option on common cloud services. Multi-factor authentication is already built into these services, and it won't cost anything other than a small amount of training time to try them.
  6. How will a password reset be handled in a multi-factor authentication environment? Ideally, any reset or recovery process should be at least as strong as the multi-factor authentication process itself. There should be ‘secret questions’ a user would answer, or an SMS code might be sent to a recognized email or phone number.

What Are the Obstacles to Implementing Multi-Factor Authentication?

Making a business case for multifactor authentication clearly requires some advanced planning. There are many use cases for the technology that can be applied in different ways to different parts of an IT infrastructure. Understanding how MFA will be used ahead of time will be helpful when it comes time to selecting a provider.

Before you begin the task of picking a multi-factor authentication vendor, carefully consider the following possible obstacles to deployment:

  1. If your Active Directory is not lean and accurate, implementing a MFA solution will be a painful way to get there.
  2. If you still use mostly on-premises servers, you might be better off using (or at least starting with) Windows Server's built-in password-strengthening policies. This will allow you to gauge how much resistance there is from users when they have to regularly change their passwords and make them more complex.
  3. If your company has a geographically-distributed staff, with a few people in many cities, it may be difficult to train the user population or disseminate physical key fobs. In such cases, enterprises may want to look into software tokens or software apps instead.

The Future of Multi-Factor Authentication

MFA has become a more mainstream option for financial firms and other consumer-facing businesses. In 2014, more than 1800 respondents to a Ponemon Institute survey indicated that their organizations planned to adopt some form of multi-factor authentication, while another 40 percent were considering it. As passwords become increasingly insecure, and as our mobile, cloud-based computing becomes more prevalent, multi-factor tools are finding use in just about every corner of the enterprise, especially where personal information is being consumed. For example, Symantec Validation and ID Protection Service is a highly scalable, cloud-based solution that delivers highly secure multi-factor authentication for enterprises of all sizes.

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