Office 365 logging has been enabled

// Copyright 2025 Google LLC. Licensed under Apache-2.0.

rule o365_logging_enabled {

  meta:
    author = "Google Cloud Security"
    description = "Detect when the Unified Audit Log is enabled"
    rule_id = "mr_a45012d7-4430-4666-b172-5488a48e9ca6"
    rule_name = "Office 365 logging has been enabled"
    assumption = "If logging is expected, there is no reason for this to be switched off. If it has been disabled and then this event triggers, it has been enabled which may indicate a gap in logging."
    tactic = "TA0005"
    technique = "T1562.008"
    type = "alert"
    platform = "azure"
    data_source = "o365"
    severity = "Critical"
    priority = "Critical"

  events:
    $log.metadata.event_type = "SETTING_CREATION"
    $log.metadata.product_event_type = "Set-AdminAuditLogConfig"
    $log.metadata.product_name = "Office 365"
    $log.metadata.vendor_name = "Microsoft"
    $log.security_result.detection_fields["UnifiedAuditLogIngestionEnabled"] = "True"
    $log.principal.user.userid = $user

  match:
    $user over 5m

  outcome:
    $risk_score = 85
    $event_count = count_distinct($log.metadata.id)
    $referral_url = array_distinct($log.network.http.referral_url)
    $user_agent = array_distinct($log.network.http.user_agent)
    $principal_application = array_distinct($log.principal.application)
    $principal_ip = array_distinct($log.principal.ip)
    $target_application = array_distinct($log.target.application)
    //$principal_user_email_address = array_distinct(principal.user.email_addresses)
    //$principal_user_userid = array_distinct($log.principal.user.userid)
    $session = array_distinct($log.network.session_id)
    $location = array_distinct(strings.coalesce($log.principal.location.state,$log.principal.location.country_or_region))
    $target_resource_resource_type = array_distinct($log.target.resource.resource_type)
    $target_url = array_distinct($log.target.url)

  condition:
    $log
}