MFA Options for Small Businesses: Which Method Should You Use?

Multifactor authentication has become one of the most important controls a small business can use to protect email, cloud applications, financial systems, remote access, and administrative accounts.

However, enabling MFA is not the end of the decision. Businesses must also decide which authentication methods to permit. A physical security key, a passkey, an authenticator notification, and a text-message code may all be called MFA, but they do not provide the same protection.

This guide compares the most common MFA options for small businesses and explains how to choose methods that match the risk, workforce, devices, and recovery needs of the organization.

What Is Multifactor Authentication?

Multifactor authentication, commonly called MFA, requires a user to prove identity with more than one type of evidence. These factors generally include something the person knows, something the person has, or something the person is.

A password is something the user knows. A registered device or security key is something the user has. A fingerprint or facial scan is something the user is.

The purpose of MFA is to stop an attacker who has obtained a password from immediately taking over the account. That protection is valuable, but the strength of the result depends heavily on the method being used.

Which MFA Option Provides the Strongest Protection?

For most businesses, phishing-resistant MFA provides the strongest practical protection. Phishing-resistant methods are designed so that a user cannot easily enter or relay an authentication code to a fraudulent website.

Passkeys and FIDO2 security keys use public-key cryptography tied to the legitimate website or application. If an employee is directed to a fake Microsoft 365 login page, the passkey should not authenticate that fraudulent site.

That is a major improvement over passwords, SMS codes, and one-time codes that can be entered into a convincing phishing page.

How Do the Main MFA Options Compare?

Method	Protection	Best Use	Main Limitation
Passkey or FIDO2 security key	Phishing-resistant	Administrators, executives, finance, regulated or sensitive access	Requires planning, compatible systems, and recovery procedures
Authenticator app with number matching	Strong, but still phishable	General employees and broad deployments	Relies on a registered device and attentive users
Authenticator app with one-time code	Moderate	Applications that do not support stronger methods	The code can be captured by a phishing site
SMS text-message code	Limited	Fallback when stronger methods are unavailable	Phishing, number transfer, mobile-service, and delivery risks
Email code	Weak	Last-resort fallback	Provides little separation if the email account is already compromised

What Are Passkeys?

A passkey replaces a reusable password with a cryptographic credential. The private portion remains on an approved device or in a passkey provider, while the service stores the corresponding public key.

The user normally unlocks the passkey with a device PIN, fingerprint, or facial recognition. The biometric data stays on the device and is used to unlock the credential. It is not sent to the website as the user’s password.

Microsoft describes passkeys using the FIDO2 standard as phishing-resistant credentials. Microsoft Entra ID supports both device-bound and synced passkeys, and passkeys are available across Entra ID editions, including Entra ID Free. Organizations still need to configure which passkey types they allow and how recovery works.

When Should a Business Use Physical Security Keys?

A physical security key is a small device that connects through USB, NFC, or another supported method. It provides strong phishing resistance because the key verifies the legitimate service before completing authentication.

Security keys are particularly appropriate for:

• Global administrators and other privileged IT accounts
• Owners and executives with broad access
• Accounting employees who manage payments or banking
• Law firms and regulated organizations handling sensitive information
• Employees who cannot or should not use a personal phone for business authentication

The business should issue at least one backup method and define what happens when a key is lost. Simply handing out keys without enrollment, inventory, recovery, and removal procedures creates unnecessary support problems.

Are Authenticator Apps a Good Option?

Authenticator apps remain a practical choice for many small businesses. Number matching is preferable to a simple approve-or-deny notification because the user must enter the number shown on the sign-in screen. This helps reduce accidental approvals and routine MFA fatigue attacks.

However, number matching is not fully phishing-resistant. A convincing attacker may still persuade someone to interact with an authentication request. Businesses should teach employees never to approve an unexpected prompt and to report repeated or unexplained requests.

Our article Social Engineering Attacks: How Businesses Can Recognize and Stop Them explains why identity verification must combine technology with clear employee procedures.

Should Employees Be Required to Use Personal Phones for MFA?

This question is often overlooked. Requiring employees to install a business authenticator app on a personal phone may create resistance, inconsistent enrollment, privacy concerns, and complications when a device is replaced or an employee leaves.

The authenticator app does not normally give the employer general access to the employee’s personal phone. Even so, a business should not assume that every employee owns a compatible smartphone or is willing to use it for work.

If the company does not provide phones, it should establish an alternative. Options may include a company-issued security key, a supported hardware token, or another approved authentication method. The policy should explain who pays for required equipment, how it is replaced, and what employees should do when the device is unavailable.

Security should not depend on an informal expectation that employees will supply personal equipment without discussion.

Why Are SMS and Email Codes Weaker?

SMS codes can be intercepted through phishing and may also be affected by phone-number transfers, service disruptions, or changes in employee phone numbers. They still provide more protection than a password alone, but they should not be the preferred method for sensitive access.

Email codes may be even less useful when the email account is the system being protected or when the same compromised mailbox receives the code. MFA should create meaningful separation between factors. Sending the second factor into an already-compromised channel weakens that separation.

Which Accounts Should Receive the Strongest MFA First?

Start with accounts where compromise would create the greatest business impact. These include Microsoft 365 administrators, remote-access accounts, financial applications, payroll, password managers, backup systems, domain registrars, and security platforms.

Executives, finance teams, IT administrators, human resources personnel, and employees with access to sensitive client information should also receive stronger methods early.

Conditional Access can help apply different requirements based on the user, resource, device, location, and risk. See PCC’s Conditional Access Guide for Small Businesses for a plain-English explanation.

MFA Requires an Account-Recovery Plan

A strong authentication method can fail operationally if the company has no safe recovery process. Employees lose phones. Keys go missing. People replace devices. Administrators leave unexpectedly.

Recovery should not rely on a help-desk employee accepting a caller’s word that a device was lost. The business needs a documented identity-verification procedure before MFA methods are reset or replaced.

Maintain more than one emergency administrator account, protect those accounts with strong independent methods, monitor their use, and never share a routine administrator login among technicians.

What MFA Approach Should Most Small Businesses Use?

A practical approach is to require phishing-resistant passkeys or security keys for administrators and high-impact roles, then expand them as application and device support permits. Authenticator apps with number matching can protect the broader workforce during the transition.

SMS should remain a fallback rather than the default, and email codes should be avoided when they do not provide a truly separate factor.

The right answer is rarely one identical method for every employee and every application. It is a controlled set of approved methods matched to risk, supported by enrollment, recovery, monitoring, and offboarding procedures.

Frequently Asked Questions About MFA Options for Small Businesses

Is any MFA better than no MFA?

Generally, yes. Even weaker MFA can stop an attacker who has only a password. However, businesses should move sensitive accounts toward phishing-resistant methods rather than treating every MFA option as equivalent.

Are passkeys the same as passwords saved in a browser?

No. A saved password is still a reusable secret. A passkey uses a cryptographic key pair and is bound to the legitimate service, which provides stronger resistance to phishing.

Do employees need company phones to use MFA?

No. A business can provide security keys or other supported hardware methods. If personal phones are permitted, the organization should document expectations, privacy boundaries, support, and alternatives.

Should every administrator have two security keys?

A backup authentication method is advisable, but it must be registered, secured, inventoried, and removed when no longer needed. Recovery design should be based on the organization’s platform and risk.

Can MFA stop every account takeover?

No. Attackers may steal active sessions, trick help desks, abuse application permissions, or persuade users to approve requests. MFA should be combined with Conditional Access, monitoring, secure recovery, least privilege, and employee training.

Related Reading

Read The 23andMe Lawsuit Is a Warning About Password Reuse Risks for Businesses.

Learn how Conditional Access adds context and policy to authentication decisions.

Explore Managed Detection and Response and why authentication alerts still require investigation.

About Professional Computer Concepts

Professional Computer Concepts (PCC) is a trusted Managed IT and Cybersecurity provider serving the Bay Area for over 20 years. We help small and midsize businesses simplify their IT, strengthen security, and modernize operations. Explore our services:

Managed IT Services | Cybersecurity | Cloud Solutions

From PCC’s Desk

MFA should not become a checkbox that a business marks complete and never reviews again. The method matters, recovery matters, and the accounts receiving the strongest protection matter.

If you need help reviewing authentication methods, administrator accounts, or Conditional Access settings, let’s talk.