Valimail Enforce - DMARC Policy Weakened to None

ValimailEnforceEvents_CL
| where EventSeverity == "High"
| where EventType == "dmarc_policy_set_to_none"
| summarize
    EventCount = count(),
    FirstSeen = min(PerformedAt),
    LastSeen = max(PerformedAt),
    Changes = make_set(EventChange)
  by Subject, User, EventCategory
| extend
    AccountName = tostring(split(User, "@")[0]),
    AccountDomain = tostring(split(User, "@")[1]),
    DomainName = Subject

entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountDomain
- entityType: DNS
  fieldMappings:
  - identifier: DomainName
    columnName: DomainName
name: Valimail Enforce - DMARC Policy Weakened to None
kind: Scheduled
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/ValimailEnforce/Analytic%20Rules/ValimailEnforce_DMARCPolicyWeakened.yaml
triggerOperator: gt
status: Available
queryPeriod: 1h
requiredDataConnectors:
- connectorId: ValimailEnforce
  dataTypes:
  - ValimailEnforceEvents_CL
tactics:
- DefenseEvasion
- InitialAccess
query: |
  ValimailEnforceEvents_CL
  | where EventSeverity == "High"
  | where EventType == "dmarc_policy_set_to_none"
  | summarize
      EventCount = count(),
      FirstSeen = min(PerformedAt),
      LastSeen = max(PerformedAt),
      Changes = make_set(EventChange)
    by Subject, User, EventCategory
  | extend
      AccountName = tostring(split(User, "@")[0]),
      AccountDomain = tostring(split(User, "@")[1]),
      DomainName = Subject
description: |
  This query searches for DMARC policies changed to 'none', which disables enforcement
  and leaves the domain vulnerable to spoofing and phishing attacks.
severity: High
incidentConfiguration:
  groupingConfiguration:
    lookbackDuration: 1d
    groupByEntities:
    - DNS
    enabled: true
    matchingMethod: Selected
    reopenClosedIncident: false
  createIncident: true
id: 44ec1fa4-a502-41ae-879a-3aad3557edce
triggerThreshold: 0
queryFrequency: 1h
alertDetailsOverride:
  alertDescriptionFormat: |
    The DMARC policy for domain '{{Subject}}' was set to 'none' by '{{User}}',
    disabling email authentication enforcement. This may expose the domain to spoofing.
  alertDisplayNameFormat: DMARC policy set to NONE on domain {{Subject}} by {{User}}
version: 1.0.0
relevantTechniques:
- T1566
- T1562

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/44ec1fa4-a502-41ae-879a-3aad3557edce')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/44ec1fa4-a502-41ae-879a-3aad3557edce')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "The DMARC policy for domain '{{Subject}}' was set to 'none' by '{{User}}',\ndisabling email authentication enforcement. This may expose the domain to spoofing.\n",
          "alertDisplayNameFormat": "DMARC policy set to NONE on domain {{Subject}} by {{User}}"
        },
        "alertRuleTemplateName": "44ec1fa4-a502-41ae-879a-3aad3557edce",
        "customDetails": null,
        "description": "This query searches for DMARC policies changed to 'none', which disables enforcement\nand leaves the domain vulnerable to spoofing and phishing attacks.\n",
        "displayName": "Valimail Enforce - DMARC Policy Weakened to None",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountDomain",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "DNS",
            "fieldMappings": [
              {
                "columnName": "DomainName",
                "identifier": "DomainName"
              }
            ]
          }
        ],
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": true,
            "groupByEntities": [
              "DNS"
            ],
            "lookbackDuration": "P1D",
            "matchingMethod": "Selected",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/ValimailEnforce/Analytic%20Rules/ValimailEnforce_DMARCPolicyWeakened.yaml",
        "query": "ValimailEnforceEvents_CL\n| where EventSeverity == \"High\"\n| where EventType == \"dmarc_policy_set_to_none\"\n| summarize\n    EventCount = count(),\n    FirstSeen = min(PerformedAt),\n    LastSeen = max(PerformedAt),\n    Changes = make_set(EventChange)\n  by Subject, User, EventCategory\n| extend\n    AccountName = tostring(split(User, \"@\")[0]),\n    AccountDomain = tostring(split(User, \"@\")[1]),\n    DomainName = Subject\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "High",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion",
          "InitialAccess"
        ],
        "techniques": [
          "T1562",
          "T1566"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}