# yaml-language-server: $schema=../../../../schema/control.schema.json
id: CB-M365-AUTH-032
title: Define the organization's trusted network locations
finding:
  title: No trusted network locations are defined in Conditional Access
  description: Policies cannot tell corporate egress addresses from the rest of the internet, and ID Protection loses a signal to rate sign-in risk.
status: active
profiles: [hardened]
risk:
  severity: low
assessment: manual
tags: [conditional-access, named-locations, network]

applicability:
  requires:
    - "Microsoft Entra ID P1"

description: |
  The public IP ranges used by the organization to reach Microsoft 365 (internet egress of offices,
  data centers, VPN concentrators, cloud proxy) are declared as **IP ranges** named locations in
  Conditional Access and marked as **trusted**. The list is owned by the network team and reviewed
  when egress points change.
rationale: |
  Trusted locations reduce false positives in ID Protection (sign-ins from them are rated lower
  risk) and let administrators write precise policies, for example restricting security info
  registration or service accounts to the corporate network (CB-M365-AUTH-019). A missing or stale
  list leads to broad exclusions instead.
impact: |
  None by itself: a named location changes nothing until a policy uses it. Do not use a trusted
  location as a reason to skip MFA for everyone; an attacker on the corporate network or on a
  compromised device inside it would then bypass it.
notes: |
  Only public egress addresses count; private ranges (10.0.0.0/8 and similar) are never seen by
  Microsoft Entra ID. With a cloud proxy or SSE solution, declare the proxy's egress ranges, or use
  Global Secure Access source IP restoration.

audit:
  manual: |
    1. Sign in to the Microsoft Entra admin center (https://entra.microsoft.com) as at least a
       Security Reader.
    2. Browse to **Entra ID** > **Conditional Access** > **Named locations**.
    3. Check that at least one **IP ranges** location exists with **Trusted** set to **Yes**, and
       that its ranges match the current list of corporate egress addresses provided by the network
       team.
    4. Alternative in PowerShell (Microsoft Graph, scope `Policy.Read.All`):
       `Get-MgIdentityConditionalAccessNamedLocation | Where-Object { $_.AdditionalProperties.isTrusted } | Select-Object DisplayName, @{n='Ranges';e={$_.AdditionalProperties.ipRanges.cidrAddress}}`
    5. Fail if no trusted IP location exists, or if it contains ranges the organization does not own
       or no longer uses.

remediation:
  manual: |
    1. Get the list of public egress IP ranges from the network team.
    2. Sign in to the Microsoft Entra admin center as at least a Conditional Access Administrator.
    3. Browse to **Entra ID** > **Conditional Access** > **Named locations** > **IP ranges
       location**.
    4. Enter a name, add each range in CIDR notation, select **Mark as trusted location** and
       **Create**.
    5. Record the owner of the list and review it at each network change.

    In PowerShell: `New-MgIdentityConditionalAccessNamedLocation` with `@odata.type`
    `#microsoft.graph.ipNamedLocation`, `ipRanges` and `isTrusted = $true`.
  rollback: |
    Clear **Mark as trusted location**, or delete the location once no policy references it.

references:
  - title: Network-based Conditional Access - named locations
    url: https://learn.microsoft.com/entra/identity/conditional-access/concept-assignment-network
    publisher: Microsoft
    kind: vendor-doc
    accessed: 2026-10-24
mappings:
  - framework: cis-m365
    framework_version: "7.0.0"
    id: "5.2.2.14"
    relation: equivalent
  - framework: nist-800-53r5
    framework_version: "5.1.1"
    id: AC-3
    relation: related
related_controls:
  - id: CB-M365-AUTH-033
    type: related
  - id: CB-M365-AUTH-019
    type: related

authors:
  - name: Alice
    github: Sn0wAlice
introduced_in: 0.1.0
created: 2026-10-24
updated: 2026-10-24