GSA Enriched Office 365 - Exchange AuditLog Disabled

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Id	dc451755-8ab3-4059-b805-e454c45d1d44
Rulename	GSA Enriched Office 365 - Exchange AuditLog Disabled
Description	Identifies when the Exchange audit logging has been disabled, which may indicate an adversary attempt to evade detection or bypass other defenses.
Severity	Medium
Tactics	DefenseEvasion
Techniques	T1562
Required data connectors	AzureActiveDirectory Office365
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Analytic Rules/Office 365 - exchange_auditlogdisabled.yaml
Version	2.0.8
Arm template	dc451755-8ab3-4059-b805-e454c45d1d44.json

KQL

// OfficeActivity Query
let OfficeEvents = OfficeActivity
    | where OfficeWorkload =~ "Exchange" 
    | where UserType in~ ("Admin", "DcAdmin")
    // Only admin or global-admin can disable audit logging
    | where Operation =~ "Set-AdminAuditLogConfig"
    | extend ParsedParameters = parse_json(Parameters)
    | extend AdminAuditLogEnabledValue = tostring(ParsedParameters[3].Value)
    | where AdminAuditLogEnabledValue =~ "False"
    | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), OperationCount = count() 
        by Operation, UserType, UserId, ClientIP, ResultStatus, Parameters, AdminAuditLogEnabledValue
    | extend AccountName = iff(UserId contains '@', tostring(split(UserId, '@')[0]), 
                        iff(UserId contains '\\', tostring(split(UserId, '\\')[1]), UserId))
    | extend AccountUPNSuffix = iff(UserId contains '@', tostring(split(UserId, '@')[1]), '')
    | extend AccountNTDomain = iff(UserId contains '\\', tostring(split(UserId, '\\')[0]), '');
// EnrichedMicrosoft365AuditLogs Query
let EnrichedEvents = EnrichedMicrosoft365AuditLogs
    | where Workload =~ "Exchange"
    | where UserType in~ ("Admin", "DcAdmin")
    | where Operation =~ "Set-AdminAuditLogConfig"
    | extend ParsedParameters = parse_json(AdditionalProperties.Parameters)
    | extend AdminAuditLogEnabledValue = tostring(ParsedParameters[3].Value)
    | where AdminAuditLogEnabledValue =~ "False"
    | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), OperationCount = count() 
        by Operation, UserType, UserId, ClientIP = SourceIp, ResultStatus, Parameters = tostring(AdditionalProperties.Parameters), AdminAuditLogEnabledValue
    | extend AccountName = iff(UserId contains '@', tostring(split(UserId, '@')[0]), 
                        iff(UserId contains '\\', tostring(split(UserId, '\\')[1]), UserId))
    | extend AccountUPNSuffix = iff(UserId contains '@', tostring(split(UserId, '@')[1]), '')
    | extend AccountNTDomain = iff(UserId contains '\\', tostring(split(UserId, '\\')[0]), '');
// Combine Office and Enriched Events and Deduplicate
let CombinedEvents = OfficeEvents
    | union EnrichedEvents
    | summarize arg_min(StartTimeUtc, *) by Operation, UserId, ClientIP;
// Project Final Output
CombinedEvents
    | project StartTimeUtc, EndTimeUtc, Operation, UserType, UserId, ClientIP, ResultStatus, Parameters, AdminAuditLogEnabledValue, AccountName, AccountUPNSuffix, AccountNTDomain

YAML

relevantTechniques:
- T1562
name: GSA Enriched Office 365 - Exchange AuditLog Disabled
requiredDataConnectors:
- dataTypes:
  - EnrichedMicrosoft365AuditLogs
  connectorId: AzureActiveDirectory
- dataTypes:
  - OfficeActivity (Exchange)
  connectorId: Office365
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: UserId
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountUPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: ClientIP
  entityType: IP
triggerThreshold: 0
id: dc451755-8ab3-4059-b805-e454c45d1d44
tactics:
- DefenseEvasion
version: 2.0.8
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Analytic Rules/Office 365 - exchange_auditlogdisabled.yaml
queryPeriod: 1d
kind: Scheduled
queryFrequency: 1d
severity: Medium
status: Available
description: |
    Identifies when the Exchange audit logging has been disabled, which may indicate an adversary attempt to evade detection or bypass other defenses.
query: |
  // OfficeActivity Query
  let OfficeEvents = OfficeActivity
      | where OfficeWorkload =~ "Exchange" 
      | where UserType in~ ("Admin", "DcAdmin")
      // Only admin or global-admin can disable audit logging
      | where Operation =~ "Set-AdminAuditLogConfig"
      | extend ParsedParameters = parse_json(Parameters)
      | extend AdminAuditLogEnabledValue = tostring(ParsedParameters[3].Value)
      | where AdminAuditLogEnabledValue =~ "False"
      | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), OperationCount = count() 
          by Operation, UserType, UserId, ClientIP, ResultStatus, Parameters, AdminAuditLogEnabledValue
      | extend AccountName = iff(UserId contains '@', tostring(split(UserId, '@')[0]), 
                          iff(UserId contains '\\', tostring(split(UserId, '\\')[1]), UserId))
      | extend AccountUPNSuffix = iff(UserId contains '@', tostring(split(UserId, '@')[1]), '')
      | extend AccountNTDomain = iff(UserId contains '\\', tostring(split(UserId, '\\')[0]), '');
  // EnrichedMicrosoft365AuditLogs Query
  let EnrichedEvents = EnrichedMicrosoft365AuditLogs
      | where Workload =~ "Exchange"
      | where UserType in~ ("Admin", "DcAdmin")
      | where Operation =~ "Set-AdminAuditLogConfig"
      | extend ParsedParameters = parse_json(AdditionalProperties.Parameters)
      | extend AdminAuditLogEnabledValue = tostring(ParsedParameters[3].Value)
      | where AdminAuditLogEnabledValue =~ "False"
      | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), OperationCount = count() 
          by Operation, UserType, UserId, ClientIP = SourceIp, ResultStatus, Parameters = tostring(AdditionalProperties.Parameters), AdminAuditLogEnabledValue
      | extend AccountName = iff(UserId contains '@', tostring(split(UserId, '@')[0]), 
                          iff(UserId contains '\\', tostring(split(UserId, '\\')[1]), UserId))
      | extend AccountUPNSuffix = iff(UserId contains '@', tostring(split(UserId, '@')[1]), '')
      | extend AccountNTDomain = iff(UserId contains '\\', tostring(split(UserId, '\\')[0]), '');
  // Combine Office and Enriched Events and Deduplicate
  let CombinedEvents = OfficeEvents
      | union EnrichedEvents
      | summarize arg_min(StartTimeUtc, *) by Operation, UserId, ClientIP;
  // Project Final Output
  CombinedEvents
      | project StartTimeUtc, EndTimeUtc, Operation, UserType, UserId, ClientIP, ResultStatus, Parameters, AdminAuditLogEnabledValue, AccountName, AccountUPNSuffix, AccountNTDomain  
triggerOperator: gt

ARM

{
  "$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/dc451755-8ab3-4059-b805-e454c45d1d44')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/dc451755-8ab3-4059-b805-e454c45d1d44')]",
      "properties": {
        "alertRuleTemplateName": "dc451755-8ab3-4059-b805-e454c45d1d44",
        "customDetails": null,
        "description": "Identifies when the Exchange audit logging has been disabled, which may indicate an adversary attempt to evade detection or bypass other defenses.\n",
        "displayName": "GSA Enriched Office 365 - Exchange AuditLog Disabled",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "UserId",
                "identifier": "FullName"
              },
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountUPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "ClientIP",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Analytic Rules/Office 365 - exchange_auditlogdisabled.yaml",
        "query": "// OfficeActivity Query\nlet OfficeEvents = OfficeActivity\n    | where OfficeWorkload =~ \"Exchange\" \n    | where UserType in~ (\"Admin\", \"DcAdmin\")\n    // Only admin or global-admin can disable audit logging\n    | where Operation =~ \"Set-AdminAuditLogConfig\"\n    | extend ParsedParameters = parse_json(Parameters)\n    | extend AdminAuditLogEnabledValue = tostring(ParsedParameters[3].Value)\n    | where AdminAuditLogEnabledValue =~ \"False\"\n    | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), OperationCount = count() \n        by Operation, UserType, UserId, ClientIP, ResultStatus, Parameters, AdminAuditLogEnabledValue\n    | extend AccountName = iff(UserId contains '@', tostring(split(UserId, '@')[0]), \n                        iff(UserId contains '\\\\', tostring(split(UserId, '\\\\')[1]), UserId))\n    | extend AccountUPNSuffix = iff(UserId contains '@', tostring(split(UserId, '@')[1]), '')\n    | extend AccountNTDomain = iff(UserId contains '\\\\', tostring(split(UserId, '\\\\')[0]), '');\n// EnrichedMicrosoft365AuditLogs Query\nlet EnrichedEvents = EnrichedMicrosoft365AuditLogs\n    | where Workload =~ \"Exchange\"\n    | where UserType in~ (\"Admin\", \"DcAdmin\")\n    | where Operation =~ \"Set-AdminAuditLogConfig\"\n    | extend ParsedParameters = parse_json(AdditionalProperties.Parameters)\n    | extend AdminAuditLogEnabledValue = tostring(ParsedParameters[3].Value)\n    | where AdminAuditLogEnabledValue =~ \"False\"\n    | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), OperationCount = count() \n        by Operation, UserType, UserId, ClientIP = SourceIp, ResultStatus, Parameters = tostring(AdditionalProperties.Parameters), AdminAuditLogEnabledValue\n    | extend AccountName = iff(UserId contains '@', tostring(split(UserId, '@')[0]), \n                        iff(UserId contains '\\\\', tostring(split(UserId, '\\\\')[1]), UserId))\n    | extend AccountUPNSuffix = iff(UserId contains '@', tostring(split(UserId, '@')[1]), '')\n    | extend AccountNTDomain = iff(UserId contains '\\\\', tostring(split(UserId, '\\\\')[0]), '');\n// Combine Office and Enriched Events and Deduplicate\nlet CombinedEvents = OfficeEvents\n    | union EnrichedEvents\n    | summarize arg_min(StartTimeUtc, *) by Operation, UserId, ClientIP;\n// Project Final Output\nCombinedEvents\n    | project StartTimeUtc, EndTimeUtc, Operation, UserType, UserId, ClientIP, ResultStatus, Parameters, AdminAuditLogEnabledValue, AccountName, AccountUPNSuffix, AccountNTDomain\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1562"
        ],
        "templateVersion": "2.0.8",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}