Multifactor 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 VPN1. MFA is a core component of a strong identity and access management (IAM) policy. MFA can help prevent an attacker from stealing usernames and passwords of users within an organization by adding an extra layer of security beyond the traditional username and password. For example, a user may need to enter a one-time code sent to their phone or email, scan their fingerprint, or use a hardware token to prove their identity. This way, even if an attacker obtains the user’s credentials, they cannot access the resource without the second factor2.

The other options are not technologies that can help prevent an attacker from stealing usernames and passwords of users within an organization. RADIUS-based REAP is a protocol that allows wireless clients to authenticate with a RADIUS server, but it does not provide MFA3. Fingerprinting is a technique that identifies the operating system or application of a device based on its network characteristics, but it does not provide MFA4. Dynamic ARP Inspection is a security feature that prevents ARP spoofing attacks by validating ARP packets, but it does not provide MFA5.

References := 1: What is Multi-Factor Authentication (MFA)? | OneLogin(https://www.onelogin.com/learn/what-is-mfa) 2: What is: Multifactor Authentication - Microsoft Support(https://support.microsoft.com/en-us/topic/what-is-multifactor-authentication-e5e39437-121c-be60-d123-eda06bddf661) 3: Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0, Module 3: Securing the Network, Lesson 3.3: Secure Wireless Connectivity, Topic 3.3.1: Wireless Security Protocols, page 3-40. 4: Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0, Module 2: Securing the Cloud, Lesson 2.2: Cloud Security Assessment, Topic 2.2.1: Cloud Security Concepts, page 2-13. 5: Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0, Module 3: Securing the Network, Lesson 3.2: Secure Network Access, Topic 3.2.2: Layer 2 Security Features, page 3-19.