What is Multi-Factor Authentication (MFA) and How Does it Work?

Multi-factor Authentication (MFA) is an authentication method that requires the user to provide two or more verification factors to gain access to a resource such as an application, online account, or a VPN. MFA is a core component of a strong identity and access management (IAM) policy. Rather than just asking for a username and password, MFA requires one or more additional verification factors, which decreases the likelihood of a successful cyber attack.

The main benefit of MFA is it will enhance your organization's security by requiring your users to identify themselves by more than a username and password. While important, usernames and passwords are vulnerable to brute force attacks and can be stolen by third parties. Enforcing the use of an MFA factor like a thumbprint or physical hardware key means increased confidence that your organization will stay safe from cyber criminals.

MFA works by requiring additional verification information (factors). One of the most common MFA factors that users encounter are one-time passwords (OTP). OTPs are those 4-8 digit codes that you often receive via email, SMS or some sort of mobile app. With OTPs a new code is generated periodically or each time an authentication request is submitted. The code is generated based upon a seed value that is assigned to the user when they first register and some other factor which could simply be a counter that is incremented or a time value.

Most MFA authentication methodology is based on one of three types of additional information:

1. Things you know (knowledge), such as a password or PIN
2. Things you have (possession), such as a badge or smartphone
3. Things you are (inherence), such as a biometric like fingerprints or voice recognition

Examples of Multi-Factor Authentication include using a combination of these elements to authenticate:

Knowledge

• Answers to personal security questions
• Password
• OTPs (Can be both Knowledge and Possession - You know the OTP and you have to have something in your Possession to get it like your phone)

Possession

• OTPs generated by smartphone apps
• OTPs sent via text or email
• Access badges, USB devices, Smart Cards or fobs or security keys
• Software tokens and certificates

Inherence

• Fingerprints, facial recognition, voice, retina or iris scanning or other Biometrics
• Behavioral analysis

As MFA integrates machine learning and artificial intelligence (AI), authentication methods become more sophisticated, including:

Location-based

Location-based MFA usually looks at a user’s IP address and, if possible, their geo location. This information can be used to simply block a user’s access if their location information does not match what is specified on a Allow List or it might be used as an additional form of authentication in addition to other factors such as a password or OTP to confirm that user’s identity.

Adaptive Authentication or Risk-based Authentication

Another subset of MFA is Adaptive Authentication also referred to as Risk-based Authentication. Adaptive Authentication analyzes additional factors by considering context and behavior when authenticating and often uses these values to assign a level of risk associated with the login attempt. For example:

• From where is the user when trying to access information?
• When you are trying to access company information? During your normal hours or during "off hours"?
• What kind of device is used? Is it the same one used yesterday?
• Is the connection via private network or a public network?

The risk level is calculated based upon how these questions are answered and can be used to determine whether or not a user will be prompted for an additional authentication factor or whether or not they will even be allowed to log in. Thus another term used to describe this type of authentication is risk-based authentication.

With Adaptive Authentication in place, a user logging in from a cafe late at night, an activity they do not normally do, might be required to enter a code texted to the user’s phone in addition to providing their username and password. Whereas, when they log in from the office every day at 9 am they are simply prompted to provide their username and password.

Cyber criminals spend their lives trying to steal your information and an effective and enforced MFA strategy is your first line of defense against them. An effective data security plan will save your organization time and money in the future.

MFA is often used interchangeably with two-factor authentication (2FA). 2FA is basically a subset of MFA since 2FA restricts the number of factors that are required to only two factors, while MFA can be two or more.

With the advent of Cloud Computing, MFA has become even more necessary. As companies move their systems to the cloud they can no longer rely upon a user being physically on the same network as a system as a security factor. Additional security needs to be put into place to ensure that those accessing the systems are not bad actors. As users are accessing these systems anytime and from anyplace MFA can help ensure that they are who they say they are by prompting for additional authentication factors that are more difficult for hackers to imitate or use brute force methods to crack.

Many cloud based systems provide their own MFA offerings like AWS or Microsoft’s Office 365 product. Office 365 by default uses Azure Active Directory (AD) as its authentication system. And there are a few limitations. For example, you only have four basic options when it comes to what type of additional authentication factor they can use: Microsoft Authenticator, SMS, Voice and Oauth Token. You also might have to spend more on licensing depending on the types of options you want available and whether or not you want to control exactly which users will need to use MFA.

Identity as a Service (IDaaS) solutions like OneLogin offer many more MFA authentication methods when it comes to strong authentication factors and they integrate more easily with applications outside of the Microsoft ecosystem.