sap gateway acl bypass attempt

/*
 * Copyright 2026 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 sap_gateway_acl_bypass_attempt {

  meta:
    author = "Google Cloud Security"
    description = "Detects rejected connections by Gateway ACLs (secinfo/reginfo), indicating an attempt to bypass network-layer security."
    severity = "Low"
    tactic = "TA0001"
    technique = "T1190"

  events:
    $e.metadata.product_name = "SAP_GATEWAY"

    $e.additional.fields["event_action"] = /secinfo|reginfo/ nocase

    $e.security_result.action = "BLOCK"

    $source_ip = $e.principal.ip

  match:
    $source_ip over 30m

  outcome:
    $risk_score = 5
    $acl_type = array_distinct($e.additional.fields["event_action"])
    $attempted_programs = array_distinct($e.target.process.file.full_path)
    $error_details = array_distinct($e.security_result.description)
    $user_context = array_distinct($e.principal.user.userid)
    $total_denials = count($e.metadata.product_log_id)

  condition:
    $e
}