Entra ID Application Restore

/*
 * Copyright 2025 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 entra_id_application_restore {

  meta:
    author = "Google Cloud Security"
    description = "Entra ID application was restored. This implies a soft delete was performed at some point but less than 30 days ago."
    rule_id = "mr_ed0a04f9-4ceb-499e-9e6f-01e4507b8da5"
    rule_name = "Entra ID Application Restore"
    type = "alert"
    platform = "azure"
    data_source = "azure ad audit"
    severity = "Medium"
    priority = "Medium"

  events:
    $app.metadata.event_type = "SERVICE_CREATION"
    $app.metadata.product_event_type = "Restore application"
    $app.metadata.product_name = "Azure AD Directory Audit"
    $app.metadata.vendor_name = "Microsoft"
    $app.security_result.action = "ALLOW"
    $app.principal.user.userid = $user

  match:
    $user over 5m

  outcome:
    $risk_score = 65
    $event_count = count_distinct($app.metadata.id)
    $principal_ip = array_distinct($app.principal.ip)
    $principal_email = array_distinct($app.principal.user.email_addresses)
    $principal_county_region = array_distinct($app.principal.ip_geo_artifact.location.country_or_region)
    $user_agent = array_distinct($app.network.http.user_agent)
    $network_session = array_distinct($app.network.session_id)
    $target_application = array_distinct($app.target.resource.name)
    $target_application_id = array_distinct($app.target.resource.product_object_id)

  condition:
    $app
}