7.2.10 Ensure reauthentication with verification code is restricted

Information

This setting configures if guests who use a verification code to access the site or links are required to reauthenticate after a set number of days.

The recommended state is 15 or less.

Rationale:

By increasing the frequency of times guests need to reauthenticate this ensures guest user access to data is not prolonged beyond an acceptable amount of time.

Impact:

Guests who use Microsoft 365 in their organization can sign in using their work or school account to access the site or document. After the one-time passcode for verification has been entered for the first time, guests will authenticate with their work or school account and have a guest account created in the host's organization.

Note: If OneDrive and SharePoint integration with Entra ID B2B is enabled as per the CIS Benchmark the one-time-passcode experience will be replaced. Please visit Secure external sharing in SharePoint - SharePoint in Microsoft 365 | Microsoft Learn for more information.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

To remediate using the UI:

Navigate to SharePoint admin center https://admin.microsoft.com/sharepoint

Click to expand Policies > Sharing.

Scroll to and expand More external sharing settings.

Set People who use a verification code must reauthenticate after this many days to 15 or less.

To remediate using PowerShell:

Connect to SharePoint Online service using Connect-SPOService.

Run the following cmdlet:

Set-SPOTenant -EmailAttestationRequired $true -EmailAttestationReAuthDays 15

Default Value:

EmailAttestationRequired : False

EmailAttestationReAuthDays : 30

See Also

https://workbench.cisecurity.org/benchmarks/15279

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b.

Plugin: microsoft_azure

Control ID: f5aff0d1a8e1a7d7661b2f6ab79db8c800cd0992d1c1421bc0d00eb2f17d434e