Google Workspace Password Policy Changed

/*
 * 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_password_policy_changed {

  meta:
    author = "Google Cloud Security"
    description = "Identifies when Google Workspace password policy is changed. Security teams can monitor for changes to password policy configuration that may weaken the organization's security posture."
    rule_id = "mr_fd63a810-800a-4c55-97d2-080fc8a0e567"
    rule_name = "Google Workspace Password Policy Changed"
    mitre_attack_tactic = "Persistence"
    mitre_attack_technique = "Account Manipulation"
    mitre_attack_url = "https://attack.mitre.org/techniques/T1098/"
    mitre_attack_version = "v13.1"
    type = "Alert"
    data_source = "Workspace Activity"
    severity = "Low"
    priority = "Low"

  events:
    $ws.metadata.vendor_name = "Google Workspace"
    $ws.metadata.product_name = "admin"
    ($ws.metadata.product_event_type = "CREATE_APPLICATION_SETTING" or
    $ws.metadata.product_event_type = "CHANGE_APPLICATION_SETTING")
    $ws.security_result.category_details = "APPLICATION_SETTINGS"
    $ws.target.resource.name = /Password Management/
    $ws.principal.user.email_addresses = $email

  match:
    $email over 1h

  outcome:
    $risk_score = max(35)
    $mitre_attack_tactic = "Persistence"
    $mitre_attack_technique = "Account Manipulation"
    $mitre_attack_technique_id = "T1098"
    $event_count = count_distinct($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)
    $target_application =array_distinct($ws.target.application)
    $password_policies =array_distinct($ws.target.resource.name)

  condition:
    $ws
}