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1.2.1 Ensure Trusted Locations Are Defined

Information

Azure Active Directory Conditional Access allows an organization to configure Named locations and configure whether those locations are trusted or untrusted. These settings provide organizations the means to specify Geographical locations for use in conditional access policies, or define actual IP addresses and IP ranges and whether or not those IP addresses and/or ranges are trusted by the organization.

Rationale:

Defining trusted source IP addresses or ranges helps organizations create and enforce Conditional Access policies around those trusted or untrusted IP addresses and ranges. Users authenticating from trusted IP addresses and/or ranges may have less access restrictions or access requirements when compared to users that try to authenticate to Azure Active Directory from untrusted locations or untrusted source IP addresses/ranges.

Impact:

When configuring Named locations, the organization can create locations using Geographical location data or by defining source IP addresses or ranges. Configuring Named locations using a Country location does not provide the organization the ability to mark those locations as trusted, and any Conditional Access policy relying on those Countries location setting will not be able to use the All trusted locations setting within the Conditional Access policy. They instead will have to rely on the Select locations setting. This may add additional resource requirements when configuring, and will require thorough organizational testing.

In general, Conditional Access policies may completely prevent users from authenticating to Azure Active Directory, and thorough testing is recommended. To avoid complete lockout, a 'Break Glass' account with full Global Administrator rights is recommended in the event all other administrators are locked out of authenticating to Azure Active Directory. This 'Break Glass' account should be excluded from Conditional Access Policies and should be configured with the longest pass phrase feasible. This account should only be used in the event of an emergency and complete administrator lockout.

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

Solution

From Azure Portal

Navigate to the Azure AD Conditional Access Blade

Click on the Named locations blade

Within the Named locations blade, click on IP ranges location

Enter a name for this location setting in the Name text box

Click on the + sign

Add an IP Address Range in CIDR notation inside the text box that appears

Click on the Add button

Repeat steps 5 through 7 for each IP Range that needs to be added

If the information entered are trusted ranges, select the Mark as trusted location check box

Once finished, click on Create

From PowerShell
Create a new trusted IP-based Named location policy

[System.Collections.Generic.List'1[Microsoft.Open.MSGraph.Model.IpRange]]$ipRanges = @()
$ipRanges.Add('<first IP range in CIDR notation>')
$ipRanges.Add('<second IP range in CIDR notation>')
$ipRanges.Add('<third IP range in CIDR notation>')
New-AzureADMSNamedLocationPolicy -OdataType '#microsoft.graph.ipNamedLocation' -DisplayName '<name of IP Named location policy> -IsTrusted $true -IpRanges $ipRanges

Set an existing IP-based Named location policy to trusted

Set-AzureADMSNamedLocationPolicy -PolicyId '<ID of the policy>' -OdataType '#microsoft.graph.ipNamedLocation' -IsTrusted $true

Default Value:

By default, no locations are configured under the Named locations blade within the Azure AD Conditional Access blade.

See Also

https://workbench.cisecurity.org/benchmarks/10624

Item Details

References: CSCv7|11.1

Plugin: microsoft_azure

Control ID: 949d34c9de9e4ea27a40f0534637099bc5bc7504a8362f185fe3ce1fa50242d6