Which is best defined as an account security setting that requires a second form of authentication in addition to initial password?

What is single-factor authentication (SFA), two-factor authentication (2FA), and multi-factor authentication (MFA), and why is more than one factor of authentication vital to security.

First, here are the definitions:

What is Single-factor Authentication (SFA)?

Single-factor authentication is the simplest form of authentication method. With SFA, a person matches one credential to verify himself or herself online. The most popular example of this would be a password (credential) to a username. Most verification today uses this type of authentication method.

What is Two-factor Authentication (2FA)?

Two-factor authentication uses the same password/username combination, but with the addition of being asked to verify who a person is by using something only he or she owns, such as a mobile device. Putting it simply: it uses two factors to confirm an identity.

What is Multi-factor Authentication (MFA)?

Multi-factor authentication uses a combination of the following factors: something you know, something you have, and something you are. 2FA is a subset of MFA, and you can read more on the difference between the two in Chris Webber's blog, Two-Factor vs. Multi-Factor Authentication.

For more definitions, check out our cybersecurity glossary.

What are the Risks of Single-factor Authentication?

Online sites can have users' passwords leaked by a cyber criminal. Although it doesn’t happen often, it can happen! Without an additional factor to your password to confirm your identity, all a malicious user needs is your password to gain access. Hopefully, it’s not a website that has additional personal information stored, such as your credit card information, home address, or other personal information used to identify you.

Oftentimes, a user's password is simple so that it is easy to remember. Is there something wrong with that? Well, the more simple the password, the easier it is to crack or guess. A malicious user may guess your password because they know you personally or because they were able to find out certain things about you, such as your birthdate, favorite actor/actress, or pet’s name. A malicious user may also crack your password by using a bot to generate the right combination of letters/numbers to match your simple, secret identification method. In either example, it’s going to be a hassle to recover your account(s). Hopefully, your simple password is not being reused with other online entities.

SFA is quickly becoming the CDs of security measures. It was great for the time, but it’s outdated. There is a growing number of products, websites, and apps that offer two-factor and multi-factor authentication. Whether it’s just two factors, or three or more — MFA, in general, is the way to make our accounts much much harder for attackers to break into -- the time to get familiar with these new security measures is now.

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• Article
• 08/25/2022
• 20 minutes to read

In this article

To customize the end-user experience for Azure AD Multi-Factor Authentication, you can configure options for settings like account lockout thresholds or fraud alerts and notifications. Some settings are available directly in the Azure portal for Azure Active Directory (Azure AD), and some are in a separate Azure AD Multi-Factor Authentication portal.

The following Azure AD Multi-Factor Authentication settings are available in the Azure portal:

Account lockout

To prevent repeated MFA attempts as part of an attack, the account lockout settings let you specify how many failed attempts to allow before the account becomes locked out for a period of time. The account lockout settings are applied only when a PIN code is entered for the MFA prompt.

The following settings are available:

• Number of MFA denials that trigger account lockout
• Minutes until account lockout counter is reset
• Minutes until account is automatically unblocked

To configure account lockout settings, complete these steps:

1. Sign in to the Azure portal as an administrator.

2. Go to Azure Active Directory > Security > Multifactor authentication > Account lockout.

3. Enter the values for your environment, and then select Save.

   

Block and unblock users

If a user's device is lost or stolen, you can block Azure AD Multi-Factor Authentication attempts for the associated account. Any Azure AD Multi-Factor Authentication attempts for blocked users are automatically denied. Users remain blocked for 90 days from the time that they're blocked. For a video that explains how to do this, see how to block and unblock users in your tenant.

Block a user

To block a user, complete the following steps.

Watch a short video that describes this process.

1. Browse to Azure Active Directory > Security > Multifactor authentication > Block/unblock users.
2. Select Add to block a user.
3. Enter the user name for the blocked user in the format , and then provide a comment in the Reason box.
4. Select OK to block the user.

Unblock a user

To unblock a user, complete the following steps:

1. Go to Azure Active Directory > Security > Multifactor authentication > Block/unblock users.
2. In the Action column next to the user, select Unblock.
3. Enter a comment in the Reason for unblocking box.
4. Select OK to unblock the user.

Fraud alert

The fraud alert feature lets users report fraudulent attempts to access their resources. When an unknown and suspicious MFA prompt is received, users can report the fraud attempt by using the Microsoft Authenticator app or through their phone.

The following fraud alert configuration options are available:

• Automatically block users who report fraud. If a user reports fraud, the Azure AD Multi-Factor Authentication attempts for the user account are blocked for 90 days or until an administrator unblocks the account. An administrator can review sign-ins by using the sign-in report, and take appropriate action to prevent future fraud. An administrator can then unblock the user's account.

• Code to report fraud during initial greeting. When users receive a phone call to perform multi-factor authentication, they normally press # to confirm their sign-in. To report fraud, the user enters a code before pressing #. This code is 0 by default, but you can customize it. If automatic blocking is enabled, after the user presses 0# to report fraud, they need to press 1 to confirm the account blocking.

  Note

  The default voice greetings from Microsoft instruct users to press 0# to submit a fraud alert. If you want to use a code other than 0, record and upload your own custom voice greetings with appropriate instructions for your users.

To enable and configure fraud alerts, complete the following steps:

1. Go to Azure Active Directory > Security > Multifactor authentication > Fraud alert.
2. Set Allow users to submit fraud alerts to On.
3. Configure the Automatically block users who report fraud or Code to report fraud during initial greeting setting as needed.
4. Select Save.

View fraud reports

When a user reports fraud, the event shows up in the Sign-ins report (as a sign-in that was rejected by the user) and in the Audit logs.

• To view fraud reports in the Sign-ins report, select Azure Active Directory > Sign-in logs > Authentication Details. The fraud report is part of the standard Azure AD Sign-ins report and appears in the Result Detail as MFA denied, Fraud Code Entered.

• To view fraud reports in the Audit logs, select Azure Active Directory > Audit logs. The fraud report appears under Activity type Fraud reported - user is blocked for MFA or Fraud reported - no action taken based on the tenant-level settings for fraud report.

Notifications

You can configure Azure AD to send email notifications when users report fraud alerts. These notifications are typically sent to identity administrators, because the user's account credentials are likely compromised. The following example shows what a fraud alert notification email looks like:

To configure fraud alert notifications:

1. Go to Azure Active Directory > Security > Multi-Factor Authentication > Notifications.
2. Enter the email address to send the notification to.
3. To remove an existing email address, select ... next to the email address, and then select Delete.
4. Select Save.

OATH tokens

Azure AD supports the use of OATH TOTP SHA-1 tokens that refresh codes every 30 or 60 seconds. You can purchase these tokens from the vendor of your choice.

OATH TOTP hardware tokens typically come with a secret key, or seed, pre-programmed in the token. You need to input these keys into Azure AD as described in the following steps. Secret keys are limited to 128 characters, which might not be compatible with all tokens. The secret key can contain only the characters a-z or A-Z and digits 1-7. It must be encoded in Base32.

Programmable OATH TOTP hardware tokens that can be reseeded can also be set up with Azure AD in the software token setup flow.

OATH hardware tokens are supported as part of a public preview. For more information about previews, see Supplemental Terms of Use for Microsoft Azure Previews.

After you acquire tokens, you need to upload them in a comma-separated values (CSV) file format. Include the UPN, serial number, secret key, time interval, manufacturer, and model, as shown in this example:

upn,serial number,secret key,time interval,manufacturer,model
,1234567,1234567abcdef1234567abcdef,60,Contoso,HardwareKey

Note

Be sure to include the header row in your CSV file.

An administrator can sign in to the Azure portal, go to Azure Active Directory > Security > Multifactor authentication > OATH tokens, and upload the CSV file.

Depending on the size of the CSV file, it might take a few minutes to process. Select Refresh to get the status. If there are any errors in the file, you can download a CSV file that lists them. The field names in the downloaded CSV file are different from those in the uploaded version.

After any errors are addressed, the administrator can activate each key by selecting Activate for the token and entering the OTP displayed in the token.

Users can have a combination of up to five OATH hardware tokens or authenticator applications, such as the Microsoft Authenticator app, configured for use at any time.

Phone call settings

If users receive phone calls for MFA prompts, you can configure their experience, such as caller ID or the voice greeting they hear.

In the United States, if you haven't configured MFA caller ID, voice calls from Microsoft come from the following number. Uses with spam filters should exclude this number.

• +1 (855) 330-8653

Note

When Azure AD Multi-Factor Authentication calls are placed through the public telephone network, sometimes the calls are routed through a carrier that doesn't support caller ID. Because of this, caller ID isn't guaranteed, even though Azure AD Multi-Factor Authentication always sends it. This applies both to phone calls and text messages provided by Azure AD Multi-Factor Authentication. If you need to validate that a text message is from Azure AD Multi-Factor Authentication, see What SMS short codes are used for sending messages?.

To configure your own caller ID number, complete the following steps:

1. Go to Azure Active Directory > Security > Multifactor authentication > Phone call settings.
2. Set the MFA caller ID number to the number you want users to see on their phones. Only US-based numbers are allowed.
3. Select Save.

Custom voice messages

You can use your own recordings or greetings for Azure AD Multi-Factor Authentication. These messages can be used in addition to the default Microsoft recordings or to replace them.

Before you begin, be aware of the following restrictions:

• The supported file formats are .wav and .mp3.
• The file size limit is 1 MB.
• Authentication messages should be shorter than 20 seconds. Messages that are longer than 20 seconds can cause the verification to fail. If the user doesn't respond before the message finishes, the verification times out.

Custom message language behavior

When a custom voice message is played to the user, the language of the message depends on the following factors:

• The language of the user.
  • The language detected by the user's browser.
  • Other authentication scenarios might behave differently.
• The language of any available custom messages.
  • This language is chosen by the administrator when a custom message is added.

For example, if there's only one custom message, and it's in German:

• A user who authenticates in the German language will hear the custom German message.
• A user who authenticates in English will hear the standard English message.

Custom voice message defaults

You can use the following sample scripts to create your own custom messages. These phrases are the defaults if you don't configure your own custom messages.

Set up a custom message

To use your own custom messages, complete the following steps:

1. Go to Azure Active Directory > Security > Multifactor authentication > Phone call settings.
2. Select Add greeting.
3. Choose the Type of greeting, such as Greeting (standard) or Authentication successful.
4. Select the Language. See the previous section on custom message language behavior.
5. Browse for and select an .mp3 or .wav sound file to upload.
6. Select Add and then Save.

MFA service settings

Settings for app passwords, trusted IPs, verification options, and remembering multi-factor authentication on trusted devices are available in the service settings. This is a legacy portal. It isn't part of the regular Azure AD portal.

You can access service settings from the Azure portal by going to Azure Active Directory > Security > Multifactor authentication > Getting started > Configure > Additional cloud-based MFA settings. A window or tab opens with additional service settings options.

Trusted IPs

The trusted IPs feature of Azure AD Multi-Factor Authentication bypasses multi-factor authentication prompts for users who sign in from a defined IP address range. You can set trusted IP ranges for your on-premises environments. When users are in one of these locations, there's no Azure AD Multi-Factor Authentication prompt. The trusted IPs feature requires Azure AD Premium P1 edition.

Note

The trusted IPs can include private IP ranges only when you use MFA Server. For cloud-based Azure AD Multi-Factor Authentication, you can use only public IP address ranges.

IPv6 ranges are supported only in the Named locations (preview) interface.

If your organization uses the NPS extension to provide MFA to on-premises applications, the source IP address will always appear to be the NPS server that the authentication attempt flows through.

Trusted IP bypass works only from inside the company intranet. If you select the All Federated Users option and a user signs in from outside the company intranet, the user has to authenticate by using multi-factor authentication. The process is the same even if the user presents an AD FS claim.

User experience inside the corporate network

When the trusted IPs feature is disabled, multi-factor authentication is required for browser flows. App passwords are required for older rich-client applications.

When trusted IPs are used, multi-factor authentication isn't required for browser flows. App passwords aren't required for older rich-client applications if the user hasn't created an app password. After an app password is in use, the password is required.

User experience outside the corporate network

Regardless of whether trusted IPs are defined, multi-factor authentication is required for browser flows. App passwords are required for older rich-client applications.

Enable named locations by using Conditional Access

You can use Conditional Access rules to define named locations by using the following steps:

1. In the Azure portal, search for and select Azure Active Directory, and then go to Security > Conditional Access > Named locations.
2. Select New location.
3. Enter a name for the location.
4. Select Mark as trusted location.
5. Enter the IP range for your environment in CIDR notation. For example, 40.77.182.32/27.
6. Select Create.

Enable the trusted IPs feature by using Conditional Access

To enable trusted IPs by using Conditional Access policies, complete the following steps:

1. In the Azure portal, search for and select Azure Active Directory, and then go to Security > Conditional Access > Named locations.

2. Select Configure MFA trusted IPs.

3. On the Service Settings page, under Trusted IPs, choose one of these options:

   • For requests from federated users originating from my intranet: To choose this option, select the checkbox. All federated users who sign in from the corporate network bypass multi-factor authentications by using a claim that's issued by AD FS. Ensure that AD FS has a rule to add the intranet claim to the appropriate traffic. If the rule doesn't exist, create the following rule in AD FS:

     c:[Type== "https://schemas.microsoft.com/ws/2012/01/insidecorporatenetwork"] => issue(claim = c);

   • For requests from a specific range of public IPs: To choose this option, enter the IP addresses in the text box, in CIDR notation.

     • For IP addresses that are in the range xxx.xxx.xxx.1 through xxx.xxx.xxx.254, use notation like xxx.xxx.xxx.0/24.
     • For a single IP address, use notation like xxx.xxx.xxx.xxx/32.
     • Enter up to 50 IP address ranges. Users who sign in from these IP addresses bypass multi-factor authentications.

4. Select Save.

Enable the trusted IPs feature by using service settings

If you don't want to use Conditional Access policies to enable trusted IPs, you can configure the service settings for Azure AD Multi-Factor Authentication by using the following steps:

1. In the Azure portal, search for and select Azure Active Directory, and then select Users.

2. Select Per-user MFA.

3. Under multi-factor authentication at the top of the page, select service settings.

4. On the service settings page, under Trusted IPs, choose one or both of the following options:

   • For requests from federated users on my intranet: To choose this option, select the checkbox. All federated users who sign in from the corporate network bypass multi-factor authentication by using a claim that's issued by AD FS. Ensure that AD FS has a rule to add the intranet claim to the appropriate traffic. If the rule doesn't exist, create the following rule in AD FS:

     c:[Type== "https://schemas.microsoft.com/ws/2012/01/insidecorporatenetwork"] => issue(claim = c);

   • For requests from a specified range of IP address subnets: To choose this option, enter the IP addresses in the text box, in CIDR notation.

     • For IP addresses that are in the range xxx.xxx.xxx.1 through xxx.xxx.xxx.254, use notation like xxx.xxx.xxx.0/24.
     • For a single IP address, use notation like xxx.xxx.xxx.xxx/32.
     • Enter up to 50 IP address ranges. Users who sign in from these IP addresses bypass multi-factor authentications.

5. Select Save.

Verification methods

You can choose the verification methods that are available for your users in the service settings portal. When your users enroll their accounts for Azure AD Multi-Factor Authentication, they choose their preferred verification method from the options that you've enabled. Guidance for the user enrollment process is provided in Set up my account for multi-factor authentication.

The following verification methods are available:

For more information, see What authentication and verification methods are available in Azure AD?.

Enable and disable verification methods

To enable or disable verification methods, complete the following steps:

1. In the Azure portal, search for and select Azure Active Directory, and then select Users.
2. Select Per-user MFA.
3. Under multi-factor authentication at the top of the page, select service settings.
4. On the service settings page, under verification options, select or clear the appropriate checkboxes.
5. Select Save.

Remember multi-factor authentication

The remember multi-factor authentication feature lets users bypass subsequent verifications for a specified number of days, after they've successfully signed in to a device by using MFA. To enhance usability and minimize the number of times a user has to perform MFA on a given device, select a duration of 90 days or more.

Important

If an account or device is compromised, remembering MFA for trusted devices can affect security. If a corporate account becomes compromised or a trusted device is lost or stolen, you should Revoke MFA Sessions.

The revoke action revokes the trusted status from all devices, and the user is required to perform multi-factor authentication again. You can also instruct your users to restore the original MFA status on their own devices as noted in Manage your settings for multi-factor authentication.

How the feature works

The remember multi-factor authentication feature sets a persistent cookie on the browser when a user selects the Don't ask again for X days option at sign-in. The user isn't prompted again for MFA from that browser until the cookie expires. If the user opens a different browser on the same device or clears the cookies, they're prompted again to verify.

The Don't ask again for X days option isn't shown on non-browser applications, regardless of whether the app supports modern authentication. These apps use refresh tokens that provide new access tokens every hour. When a refresh token is validated, Azure AD checks that the last multi-factor authentication occurred within the specified number of days.

The feature reduces the number of authentications on web apps, which normally prompt every time. The feature can increase the number of authentications for modern authentication clients that normally prompt every 180 days, if a lower duration is configured. It might also increase the number of authentications when combined with Conditional Access policies.

Important

The remember multi-factor authentication feature isn't compatible with the keep me signed in feature of AD FS, when users perform multi-factor authentication for AD FS through MFA Server or a third-party multi-factor authentication solution.

If your users select keep me signed in on AD FS and also mark their device as trusted for MFA, the user isn't automatically verified after the remember multi-factor authentication number of days expires. Azure AD requests a fresh multi-factor authentication, but AD FS returns a token with the original MFA claim and date, rather than performing multi-factor authentication again. This reaction sets off a verification loop between Azure AD and AD FS.

The remember multi-factor authentication feature isn't compatible with B2B users and won't be visible for B2B users when they sign in to the invited tenants.

Enable remember multi-factor authentication

To enable and configure the option to allow users to remember their MFA status and bypass prompts, complete the following steps:

1. In the Azure portal, search for and select Azure Active Directory, and then select Users.
2. Select Per-user MFA.
3. Under multi-factor authentication at the top of the page, select service settings.
4. On the service settings page, under remember multi-factor authentication, select Allow users to remember multi-factor authentication on devices they trust.
5. Set the number of days to allow trusted devices to bypass multi-factor authentications. For the optimal user experience, extend the duration to 90 or more days.
6. Select Save.

Mark a device as trusted

After you enable the remember multi-factor authentication feature, users can mark a device as trusted when they sign in by selecting Don't ask again.

Next steps

To learn more, see What authentication and verification methods are available in Azure Active Directory?

What is 2 way authentication method?

What is second level authentication?

Which is a two step authentication that uses a device in addition to the password used to authenticate a user?

What is two