What Is Multi-Factor Authentication? Why Your Business Needs It

Imagine you lose your wallet. Inside is a key to your office. A stranger picks it up. Without anything else stopping them, they can walk straight in. Now imagine that key only works when paired with your fingerprint. Suddenly, losing the wallet is a much smaller problem.

That is essentially what multi-factor authentication (MFA) does for your online accounts. It means that even if a cybercriminal gets hold of your password, they still cannot get in without a second piece of proof that only you have.

According to the Australian Signals Directorate (ASD), MFA is one of the Essential Eight — the eight most effective strategies for protecting against cyber attacks. For small businesses, it is one of the quickest wins you can make today.

What Is Multi-Factor Authentication?

MFA is a security method that requires you to verify your identity in two or more ways before accessing an account. These verification methods fall into three categories:

• Something you know — a password or PIN
• Something you have — a phone, a hardware security key, or an authentication app
• Something you are — a fingerprint or face scan

When you log in with MFA enabled, you enter your password as usual. Then you are asked for a second factor — typically a six-digit code generated by an app on your phone, or a push notification asking you to approve the login.

Even if a criminal steals your password through a phishing email or a data breach, they cannot access your account without that second factor. Since they do not have your phone, they are locked out.

Why Does This Matter for Australian Small Businesses?

Password theft is extraordinarily common. Billions of username and password combinations are available for sale on the dark web right now, harvested from years of data breaches at major companies. Criminals run automated tools that try these stolen credentials across thousands of websites and services — a technique called credential stuffing.

The ASD's Annual Cyber Threat Report consistently identifies compromised credentials as one of the top ways attackers gain initial access to business systems. The good news: the report also confirms that MFA stops the vast majority of these automated attacks dead in their tracks.

Without MFA, a single breached password can unlock your email, your accounting software, your cloud storage, and your customer database. With MFA, that same stolen password is worthless on its own.

The Different Types of MFA — From Weakest to Strongest

Not all MFA is equal. Here is a breakdown from least to most secure:

SMS Text Message Codes

A code is sent to your mobile number. This is better than nothing, but criminals can sometimes intercept or redirect SMS messages through a technique called SIM swapping. It is acceptable for low-risk accounts but not ideal for your most critical systems.

Authenticator Apps

Apps like Microsoft Authenticator, Google Authenticator, or Authy generate time-based codes that expire every 30 seconds. These are not transmitted over a phone network, making them much harder to intercept. This is the recommended option for most small businesses.

Push Notifications

Apps like Microsoft Authenticator can send a push notification to your phone. You simply tap "Approve" or "Deny." This is convenient and secure, though you should always check that the location and device shown matches your actual login before approving.

Hardware Security Keys

Physical devices like a YubiKey plug into your computer or tap against your phone. These are the most secure option and are essentially impossible to phish remotely. They are worth considering for your most sensitive accounts, such as your email administrator or financial systems.

Passkeys

A newer technology that replaces passwords and a second factor with a single, highly secure login tied to your device. Passkeys are increasingly supported by Google, Apple, and Microsoft and represent the future of authentication.

Which Accounts Should You Protect with MFA?

Start with your highest-risk accounts and work outward. At a minimum, enable MFA on:

• Business email (Microsoft 365, Google Workspace) — your email is the master key to everything else, since most password resets are sent there
• Accounting and payroll software — Xero, MYOB, QuickBooks
• Cloud storage — Dropbox, OneDrive, Google Drive
• Your domain registrar and web hosting
• Banking and payment platforms
• Remote access tools — VPNs, Remote Desktop
• Social media business accounts

How to Turn On MFA: Step by Step

The exact steps vary by platform, but the general process is the same:

1. Go to your account settings or security settings
2. Look for "Two-factor authentication," "Multi-factor authentication," or "Two-step verification"
3. Choose your preferred method (authenticator app is recommended)
4. Download an authenticator app on your smartphone if you have not already
5. Scan the QR code shown on screen with your app
6. Enter the code from the app to confirm the setup
7. Save your backup codes somewhere secure — these let you in if you lose your phone

For Microsoft 365, your administrator can enforce MFA for all users through the Microsoft Entra admin centre. For Google Workspace, it is managed through the Admin console under Security > 2-step verification. Both platforms make it straightforward to require MFA across your entire organisation.

Common Questions from Business Owners

Will MFA slow my team down?

Slightly, but far less than most people expect. Modern MFA with push notifications takes about three seconds. Once your team is used to it, it becomes second nature — like buckling a seatbelt. Many platforms also offer "remember this device for 30 days" options to reduce friction on trusted devices.

What if an employee loses their phone?

This is why backup codes matter. When you set up MFA, save your backup codes in a secure location (a password manager is ideal). If your team uses Microsoft 365 or Google Workspace, administrators can also temporarily bypass MFA for a user while they recover their device.

What about shared accounts?

Shared accounts are a security risk in themselves — when everyone uses the same login, you cannot tell who did what. Where possible, give each person their own account. For systems that do require shared access, consider a shared authenticator app on a dedicated device, or use a password manager with built-in MFA support.

Key Takeaways

• MFA requires a second proof of identity beyond a password, stopping most account takeover attacks even when passwords are stolen
• Authenticator apps (Microsoft Authenticator, Google Authenticator, Authy) are the recommended MFA method for small businesses
• Start with your email, accounting software, and cloud storage — these are your highest-value targets
• MFA is one of the ASD Essential Eight — the Australian government's top recommended security controls
• Save your backup codes when setting up MFA so you are not locked out if you lose your phone
• For Microsoft 365 and Google Workspace, administrators can enforce MFA across the entire organisation

Not sure whether MFA and other essential security controls are in place across your business? Flagged is a free cyber risk assessment tool built for Australian small businesses. Run your assessment in minutes and get a clear picture of where your risks are and what to do about them.