Controls/EDCA-DATA-015.json

{
  "id": "EDCA-DATA-015",
  "title": "RPC client access connections require encryption",
  "description": "The EncryptionRequired property on the RPC client access service MUST be set to True. Requiring encryption for MAPI/RPC connections protects mailbox data in transit from clients connecting via legacy Outlook profiles.",
  "verify": true,
  "subject": "Server",
  "category": "Data Security",
  "severity": "Medium",
  "severityWeight": 5,
  "frameworks": [
    "Best Practice",
    "BSI",
    "CIS",
    "DISA"
  ],
  "references": [
    {
      "name": "CIS 2.3.6 (L1): Ensure Require client MAPI encryption is set to True",
      "url": "https://www.cisecurity.org/benchmark/microsoft_exchange_server"
    },
    {
      "name": "Set-RpcClientAccess in Exchange Server",
      "url": "https://learn.microsoft.com/powershell/module/exchange/set-rpcclientaccess"
    },
    {
      "name": "DISA STIG EX19-MB-000006: Exchange must use encryption for RPC client access (V-259645)",
      "url": "https://www.stigviewer.com/stigs/microsoft_exchange_2019_mailbox_server/2025-05-14/finding/V-259645"
    },
    {
      "name": "BSI APP.5.2.A11 — Absicherung der Kommunikation zwischen Exchange-Systemen",
      "url": "https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/Grundschutz/IT-GS-Kompendium_Einzel_PDFs_2023/06_APP_Anwendungen/APP_5_2_Microsoft_Exchange_und_Outlook_Edition_2023.pdf?__blob=publicationFile"
    }
  ],
  "remediation": {
    "automatable": true,
    "description": "Set EncryptionRequired to True on the RPC client access service.",
    "scriptTemplate": "# Require encryption for MAPI/RPC client connections.\nSet-RpcClientAccess -Server $env:COMPUTERNAME -EncryptionRequired $true"
  },
  "considerations": "Enabling encryption required may break older Outlook clients that do not support encrypted MAPI connections. Verify Outlook version compatibility before enforcing this setting.",
  "roles": [
    "Mailbox"
  ]
}