o365_logging_disabled

rule o365_logging_disabled {

  meta:
    author = "Google Cloud Security"
    description = "Detect when the Unified Audit Log is disabled"
    rule_id = "mr_17a49d19-2ea1-4d7d-9e4d-bbc7ffb07099"
    rule_name = "Office 365 logging is disabled"
    assumption = "If logging is expected, there is no reason for this to be switched off. If it is disabled a gap in logging will occur."
    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"] = "False"
    $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)
    $principal_user_userid = array_distinct($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
}