HackTool - Dumpert Process Dumper Default File

/*
 * 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 hacktool_dumpert_process_dumper_default_file {

  meta:
    author = "Florian Roth (Nextron Systems)"
    description = "Detects the creation of the default dump file used by Outflank Dumpert tool. A process dumper, which dumps the lsass process memory"
    reference = "https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_hktl_dumpert.yml"
    license = "https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md"
    rule_name = "HackTool - Dumpert Process Dumper Default File"
    sigma_uuid = "93d94efc-d7ad-4161-ad7d-1638c4f908d8"
    sigma_status = "test"
    rule_id = "mr_13ac04a7-8853-42c9-a243-9da5dc05cb66"
    tactic = "TA0006"
    technique = "T1003.001"
    data_source = "Sysmon"
    platform = "Windows"
    severity = "Critical"
    priority = "Critical"
    false_positives = "Very unlikely"

  events:
    $file.metadata.event_type = "FILE_CREATION"
    re.regex($file.target.file.full_path, `dumpert.dmp$`) nocase

    $file.principal.hostname = $hostname

  match:
    $hostname over 5m

  outcome:
    //example usage of specifying test user and hostname to adjust risk score
    $risk_score = max(if($file.principal.user.userid = "user" and $file.principal.hostname = "hostname", 0, 15))
    $principal_hostname = array_distinct($file.principal.hostname)
    $principal_process_pid = array_distinct($file.principal.process.pid)
    $principal_process_command_line = array_distinct($file.principal.process.command_line)
    $principal_process_file_sha256 = array_distinct($file.principal.process.file.sha256)
    $principal_process_file_full_path = array_distinct($file.principal.process.file.full_path)
    $principal_process_product_specific_process_id = array_distinct($file.principal.process.product_specific_process_id)
    $principal_process_parent_process_product_specific_process_id = array_distinct($file.principal.process.parent_process.product_specific_process_id)
    $principal_user_userid = array_distinct($file.principal.user.userid)
    $target_file_sha256 = array_distinct($file.target.file.sha256)
    $target_file_full_path = array_distinct($file.target.file.full_path)

  condition:
    $file
}