Controls/EDCA-MON-007.json

{
  "id": "EDCA-MON-007",
  "title": "Receive connector protocol logging is set to Verbose",
  "description": "Receive connector protocol logging records the full SMTP conversation — including EHLO, AUTH, MAIL FROM, RCPT TO, and DATA commands — for every inbound SMTP session accepted by a receive connector, providing a detailed transaction-level audit trail. Each Exchange server MUST have ProtocolLoggingLevel set to Verbose on all receive connectors. Verbose SMTP transaction logging supports security investigations, compliance auditing, and post-incident forensics.",
  "verify": true,
  "subject": "Server",
  "category": "Monitoring",
  "severity": "Medium",
  "severityWeight": 6,
  "frameworks": [
    "Best Practice",
    "CIS",
    "DISA",
    "ANSSI"
  ],
  "references": [
    {
      "name": "CIS 4.1 (L1): Ensure ProtocolLoggingLevel is set to Verbose on Receive Connectors",
      "url": "https://www.cisecurity.org/benchmark/microsoft_exchange_server"
    },
    {
      "name": "Configure protocol logging in Exchange Server",
      "url": "https://learn.microsoft.com/exchange/mail-flow/connectors/configure-protocol-logging"
    },
    {
      "name": "DISA STIG EX19-MB-000129: The Exchange global inbound message size must be controlled (V-259682)",
      "url": "https://www.stigviewer.com/stigs/microsoft_exchange_2019_mailbox_server/2025-05-14/finding/V-259682"
    },
    {
      "name": "ANSSI - Sécuriser la journalisation dans un environnement Microsoft Active Directory (2022)",
      "url": "https://messervices.cyber.gouv.fr/guides/securiser-la-journalisation-dans-un-environnement-microsoft-active-directory"
    }
  ],
  "remediation": {
    "automatable": true,
    "description": "Set ProtocolLoggingLevel to Verbose on all receive connectors.",
    "scriptTemplate": "# Enable verbose protocol logging on all receive connectors of this server.\nGet-ReceiveConnector -Server $env:COMPUTERNAME | Set-ReceiveConnector -ProtocolLoggingLevel Verbose"
  },
  "considerations": "Verbose protocol logging generates significant disk I/O on high-volume servers. Ensure that adequate disk space and a log rotation / archival policy are in place. Review log paths via Get-TransportService.",
  "roles": [
    "Mailbox",
    "Edge"
  ]
}