Google Workspace SAML IDP Configuration Change

/*
 * Copyright 2023 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES 
OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

rule google_workspace_saml_idp_configuration_change {

  meta:
    author = "Google Cloud Security"
    description = "Identifies SAML provider configuration changes in Google Workspace. Security teams can monitor for changes to SAML provider configuration that may weaken the organization's security posture."
    rule_id = "mr_1a321683-9c52-4928-a654-e0677df97c09"
    rule_name = "Google Workspace SAML IDP Configuration Change"
    mitre_attack_tactic = "Defense Evasion, Persistence, Privilege Escalation, Initial Access"
    mitre_attack_technique = "Valid Accounts"
    mitre_attack_url = "https://attack.mitre.org/techniques/T1078/"
    mitre_attack_version = "v13.1"
    type = "Alert"
    data_source = "Workspace Activity"
    severity = "High"
    priority = "High"

  events:
    $ws.metadata.vendor_name = "Google Workspace"
    $ws.metadata.product_name = "admin"
    $ws.security_result.category_details = "SAML2_SERVICE_PROVIDER_CONFIG_SETTINGS"
    $ws.metadata.product_event_type = /SAML2_SERVICE_PROVIDER_CONFIG/
    $ws.principal.user.userid = $userid

  match:
    $userid over 1h

  outcome:
    $risk_score = max(75)
    $mitre_attack_tactic = "Defense Evasion, Persistence, Privilege Escalation, Initial Access"
    $mitre_attack_technique = "Valid Accounts"
    $mitre_attack_technique_id = "T1078"
    $event_count = count_distinct($ws.metadata.id)
    $principal_ip = array_distinct($ws.principal.ip)
    $principal_country = array_distinct($ws.principal.ip_geo_artifact.location.country_or_region)
    $principal_state = array_distinct($ws.principal.ip_geo_artifact.location.state)
    $principal_user_emails = array_distinct($ws.principal.user.email_addresses)
    $principal_user_id = array_distinct($ws.principal.user.userid)
    $saml_entity_id = array_distinct($ws.about.labels["saml2_service_provider_entity_id"])
    $saml_name = array_distinct($ws.about.labels["saml2_service_provider_name"])
    $product_event_type = array_distinct($ws.metadata.product_event_type)

  condition:
    $ws
}