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Control 2.15: Network Security and Private Connectivity

Control ID: 2.15 Pillar: Security & Protection Regulatory Reference: NYDFS Part 500, FFIEC Last Verified: 2026-08-09 Governance Levels: Baseline / Recommended / Regulated

Objective

Evaluate and implement network-level security controls for Microsoft 365 Copilot traffic, including network location-based access controls, SASE / Global Secure Access, and traffic inspection capabilities. While Copilot is a cloud-native service that processes data within Microsoft's infrastructure, financial institutions must understand the network paths involved and apply appropriate network security controls. Microsoft 365 Copilot is delivered as SaaS over the public internet — apply Conditional Access, Global Secure Access (Entra Internet Access), and tenant restrictions to it. Azure Private Link does not provide a private route to the M365 Copilot service; it applies only to adjacent Azure resources an internal Copilot Studio agent may call (for example, an Azure-hosted API), where it protects that Azure resource, not Copilot.

Why This Matters for FSI

  • NYDFS Part 500 (Section 500.02) requires a cybersecurity program that protects information systems and nonpublic information — network security controls for AI service access are part of this program
  • NYDFS Part 500 (Section 500.12) requires multi-factor authentication for accessing internal networks from external networks — network-level controls supplement authentication for Copilot access
  • FFIEC IT Examination Handbook (Information Security) expects network security controls including firewalls, intrusion detection, and network segmentation — examiners will evaluate network controls for AI service traffic
  • FFIEC IT Examination Handbook (Architecture) expects secure network architecture for cloud services — Copilot's network path should be documented and controlled
  • OCC Bulletin 2023-17 expects banks to evaluate network security for outsourced services — Copilot traffic paths to Microsoft cloud infrastructure should be assessed
  • PCI DSS (if applicable) requires network segmentation and secure transmission — Copilot traffic from cardholder data environments needs specific attention

Control Description

Microsoft 365 Copilot operates as a cloud service within Microsoft's infrastructure. Network security for Copilot involves controlling how traffic flows between the organization's network and Microsoft's cloud services, and applying appropriate security controls at network boundaries.

Copilot Network Traffic Flow

User Device                    Corporate Network              Microsoft Cloud
┌──────────┐                  ┌────────────────┐            ┌──────────────────┐
│          │    Corporate     │                │   Internet │                  │
│ Copilot  │    Network       │  Firewall/     │   or SASE  │  M365 Service    │
│ Client   │ ──────────────→  │  Proxy/SASE    │ ─────────→ │  Endpoints       │
│          │                  │                │            │                  │
│          │    or Direct     │  Network       │            │  ├─ Copilot API  │
│          │    Internet      │  Controls      │            │  ├─ Graph API    │
│          │                  │                │            │  ├─ Auth (Entra) │
│          │ ──────────────→  │                │            │  └─ Bing (if web │
└──────────┘    (remote)      └────────────────┘            │     search on)   │
                                                            └──────────────────┘

Network Security Control Options

Control Description Copilot Relevance Complexity
Firewall rules Allow traffic published by the Microsoft 365 endpoint service Keep required Microsoft 365 endpoints reachable without inventing a feature-specific list Low
Web proxy/CASB Inspect and filter HTTPS traffic TLS inspection and proxy behavior can disrupt required WebSocket connectivity; validate compatibility and scope exceptions as needed Medium
SASE/SSE Secure Access Service Edge for cloud traffic Network-level access control for Copilot Medium
Global Secure Access Microsoft's SASE solution (Entra Internet Access + Private Access) Native integration with Entra CA for network-aware policies Medium
Azure Private Link Private connectivity to adjacent Azure resources (e.g., an Azure-hosted API an internal Copilot Studio agent calls) Not a private path to M365 Copilot SaaS — Microsoft offers no customer-managed private endpoints for M365/Copilot (see note below) N/A for Copilot
VPN Tunnel remote traffic through corporate network Route Copilot traffic through corporate controls Low-Medium
Split tunneling Route M365 traffic directly to internet Improves performance but reduces network inspection Medium
DNS-based controls Control resolution of M365 endpoints Basic traffic steering for Copilot services Low

Published Microsoft 365 Network Requirements for Copilot

Use the worldwide Microsoft 365 endpoint service as the authoritative firewall source. Microsoft cautions that manually maintaining granular, feature-specific FQDN lists creates an unmanageable configuration surface and connectivity incidents. In particular, copilot.microsoft.com, substrate.office.com, and *.akamaized.net are not entries in the current endpoint service and should not be represented as required endpoint-service entries.

Published Requirement URLs/Source Governance Treatment
Microsoft 365 endpoints Worldwide URLs and IP address ranges and the endpoint web service Allow the complete set applicable to the tenant; preserve Microsoft's serviceArea, category, and required metadata
Copilot WebSockets *.cloud.microsoft, *.office.com Support full WSS connectivity from user devices running Microsoft 365 applications
Selected endpoint-service entries *.cloud.microsoft, *.svc.ms, *.msecnd.net Treat these according to their published endpoint-service records, not as a complete Copilot-only allowlist
Telemetry *.events.data.microsoft.com Use the published wildcard; do not broaden it to *.data.microsoft.com
Web search Allow web search in Copilot in Cloud Policy service for Microsoft 365 Enable or disable web grounding through the documented service-side policy; don't substitute a blanket *.bing.com network block

WebSocket Requirements

Microsoft documents full WebSocket (WSS) connectivity from user devices to *.cloud.microsoft and *.office.com. Firewalls, TLS inspection devices, proxy timeouts, and protocol restrictions must not interrupt those connections.

Global Secure Access for Copilot

Microsoft Entra Global Secure Access (GSA) provides a Microsoft-native SASE solution that integrates with Conditional Access:

GSA Component Copilot Application Benefit
Entra Internet Access Secure internet-bound M365 traffic Network-aware Conditional Access for Copilot
Entra Private Access Private connectivity to on-premises resources Not directly applicable to Copilot
Compliant network check CA condition: device on compliant network Restrict Copilot to traffic through GSA
Traffic forwarding Route M365 traffic through GSA Unified policy enforcement for all M365 traffic
Universal tenant restrictions Prevent access to unauthorized tenants Block Copilot use on non-corporate tenants

Network Security Decision Matrix

Scenario Recommended Approach Rationale
All users on corporate network Firewall rules + proxy + CA location policies Traditional network perimeter adequate
Hybrid workforce (office + remote) VPN or Global Secure Access + CA policies Need consistent controls for remote and office
Fully remote workforce Global Secure Access + CA device compliance No corporate network to anchor controls
Branch offices with local internet Split tunneling + Global Secure Access Performance + security balance
Trading floors Dedicated network segment + strict firewall Highest network security for MNPI environments

Copilot Surface Coverage

M365 Application Network Controls Apply Global Secure Access Notes
Microsoft 365 Copilot Chat Yes Yes Web-based and desktop client; SaaS endpoint, no customer-managed private endpoint
Word Yes Yes Desktop and web client
Excel Yes Yes Desktop and web client
PowerPoint Yes Yes Desktop and web client
Outlook Yes Yes Desktop and web client
Teams Yes Yes Desktop and web client
OneNote Yes Yes Desktop and web client
Loop Yes Yes Web-based client
Copilot Pages Yes Yes Web-based client
SharePoint (Agents) Yes Yes Web-based access

Azure Private Link is not available for Microsoft 365 Copilot SaaS surfaces

Microsoft's networking guidance for Microsoft 365 (including Copilot surfaces) is oriented around identifying M365 traffic, allowing local branch egress to the internet, and bypassing proxies and packet inspection devices — not customer-managed Azure Private Link or private endpoints. Treat Copilot as SaaS-internet traffic and apply Conditional Access, Global Secure Access (Entra Internet Access), and tenant restrictions for tenant-aware policy enforcement. Where private connectivity is required for adjacent Azure-hosted services consumed by an internal Copilot Studio agent (for example, an Azure-hosted API the agent calls), use Private Link on the Azure resource itself; do not represent it as private connectivity to the M365 Copilot service.

Governance Levels

Level Requirement Rationale
Baseline Consume and document the Microsoft 365 endpoint service; verify TLS 1.2+ and required WSS connectivity; manage web search with the Allow web search in Copilot Cloud Policy; configure Conditional Access with named (IP-based) locations; verify proxies and TLS inspection don't interrupt Copilot connectivity Establishes basic network awareness and control — sufficient for firms with well-managed corporate networks
Recommended Implement Global Secure Access (Entra Internet Access) for M365 traffic; enable compliant network check in Conditional Access; configure universal tenant restrictions to prevent data exfiltration to unauthorized tenants; network segmentation for high-sensitivity environments (trading floors); quarterly network security review for Copilot endpoints Enhanced network controls with Microsoft-native SASE — suitable for firms with hybrid workforces needing consistent network-level controls
Regulated All Recommended requirements plus: dedicated network egress path for Copilot traffic from highest-sensitivity segments (e.g., trading floors); network traffic logging and analysis for Copilot endpoints; annual network penetration testing covering Copilot access paths; network architecture documentation included in examination packages; incident response procedures for network-level Copilot security events. (Note: Microsoft 365 Copilot is delivered as SaaS over the public internet and is not exposed via customer-managed Azure Private Link; align with Microsoft 365 networking principles — identify M365 traffic, allow local egress, and validate WSS through the network security stack.) Maximum network security aligned to Microsoft 365 networking guidance — designed for firms operating in the most restrictive network security environments, without misrepresenting private connectivity that Microsoft does not offer for SaaS Copilot surfaces.

Setup & Configuration

Step 1: Document Network Endpoints

  1. Download the current M365 network endpoints list from Microsoft
  2. Map published endpoint-service records to the Microsoft 365 service areas the organization uses; don't add unlisted feature FQDNs
  3. Document in the firm's firewall management system
  4. Subscribe to endpoint change notifications
# Download M365 endpoints programmatically
$endpoints = Invoke-RestMethod -Uri "https://endpoints.office.com/endpoints/worldwide?clientrequestid=$(New-Guid)"

# Filter for Microsoft 365 service areas used by the organization.
# Retain the endpoint service's category and required metadata in the export.
$copilotEndpoints = $endpoints | Where-Object {
  $_.serviceArea -in @("Common", "SharePoint", "Exchange", "Skype")
}

# Export for firewall configuration
$copilotEndpoints | ConvertTo-Json | Out-File "M365-Copilot-Endpoints.json"

Step 2: Configure Firewall Rules

  1. Allow traffic to all required Microsoft 365 endpoint-service entries applicable to the tenant
  2. Configure Allow web search in Copilot in Cloud Policy service for Microsoft 365 when web grounding must be restricted (see Control 2.6)
  3. Verify TLS inspection and proxy settings preserve full WSS connectivity to *.cloud.microsoft and *.office.com; apply narrowly scoped exceptions only when required by testing or published guidance
  4. Consider split tunneling for Microsoft 365 "Optimize" and "Allow" category endpoints

Portal: Microsoft Entra Admin Center > Global Secure Access

  1. Enable Entra Internet Access
  2. Configure M365 traffic forwarding profile
  3. Deploy the Global Secure Access client to managed devices
  4. Configure Conditional Access with "Compliant network" condition

Step 4: Configure Conditional Access Network Location

Portal: Microsoft Entra Admin Center > Protection > Conditional Access > Named locations

  1. Define corporate network IP ranges as trusted named locations
  2. Create CA policy requiring Copilot access from named locations or compliant network
  3. For remote users: require either VPN connection or GSA client

Step 5: Configure Universal Tenant Restrictions

Portal: Microsoft Entra Admin Center > Global Secure Access > Tenant restrictions

  1. Enable tenant restrictions v2
  2. Configure to allow access only to the corporate M365 tenant
  3. Block Copilot access on unauthorized tenants (prevents data exfiltration to personal tenants)

Step 6: Network Monitoring

  1. Configure network logging for M365 endpoints
  2. Monitor for unexpected traffic patterns to Copilot-related endpoints
  3. Set up alerts for traffic from unauthorized network segments to M365
  4. Include Copilot network traffic in the firm's SOC monitoring scope

Financial Sector Considerations

  • Trading Floor Networks: Trading environments often have the strictest network security requirements. Copilot traffic from trading floor networks should be routed through dedicated firewall rules with enhanced logging. Consider whether Copilot should be accessible from trading floor networks at all.
  • Branch Office Connectivity: Financial firms with distributed branch networks may use local internet breakout for M365 traffic (split tunneling). This improves Copilot performance but reduces corporate network visibility. Global Secure Access provides a middle ground — allowing direct internet routing while maintaining policy enforcement.
  • TLS Inspection Considerations: Many financial firms use TLS inspection proxies for security monitoring. Microsoft identifies TLS inspection as a configuration that can disrupt Copilot WebSocket connectivity. Test full WSS connectivity through the deployed proxy path and use narrowly scoped exceptions where testing or Microsoft's published endpoint guidance requires them; don't make a blanket bypass recommendation without evidence.
  • VPN Tunnel Capacity: If requiring VPN for remote Copilot access, verify that VPN infrastructure has sufficient capacity for the additional traffic. Copilot's AI processing generates relatively modest network traffic, but many concurrent users can accumulate.
  • Private Link Scope (not a Copilot path): Azure Private Link does not provide a private path to Microsoft 365 Copilot — Microsoft delivers M365/Copilot as SaaS over the public internet and offers no customer-managed private endpoints for these surfaces. Private Link is only relevant to adjacent Azure resources an internal Copilot Studio agent may call (e.g., an Azure-hosted API), where it protects that Azure resource — not the Copilot service. For M365 Copilot traffic itself, Conditional Access + Global Secure Access (Entra Internet Access) + universal tenant restrictions provide tenant-aware network policy at lower complexity.
  • Tenant Restrictions for Data Exfiltration: Universal tenant restrictions help prevent users from signing into personal or unauthorized M365 tenants and using Copilot there. This is a meaningful data exfiltration control — a user could potentially copy data to a personal tenant and use Copilot to process it outside corporate controls.
  • Examination Documentation: Network architecture documents should include Copilot traffic paths, security controls applied, and monitoring capabilities. FFIEC examiners will evaluate whether AI service traffic is adequately controlled.

Verification Criteria

  1. Endpoint Documentation: Verify that Microsoft 365 endpoint-service records are documented in the firewall management system and are current
  2. Firewall Rules: Confirm firewall rules allow the required Microsoft 365 endpoint-service records and don't depend on an unsupported feature-specific allowlist
  3. TLS Verification: Confirm that all Copilot traffic uses TLS 1.2 or higher — test from representative network locations
  4. Location-Based CA: Access Copilot from outside named locations — verify Conditional Access blocks or requires additional authentication
  5. GSA Deployment (if applicable): Verify Global Secure Access client is deployed to managed devices and M365 traffic is routed through GSA
  6. Tenant Restrictions: Attempt to sign into a personal M365 tenant from a managed device — verify access is blocked or restricted
  7. Proxy and WSS Validation: Verify full WSS connectivity to *.cloud.microsoft and *.office.com; document any narrowly scoped TLS inspection exceptions
  8. Network Segmentation: For trading floor environments, verify that Copilot traffic is appropriately segmented and logged
  9. Network Monitoring: Confirm that Copilot-related network traffic is included in SOC monitoring scope
  10. Documentation: Verify that network architecture documentation includes Copilot traffic paths and is included in examination readiness materials

Additional Resources