Impacket WMIExec CISA Report

/*
 * 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 impacket_wmiexec_cisa_report {

  meta:
    author = "Google Cloud Security"
    description = "Detects the artifacts generally associated with the use of wmiexec.py"
    rule_id = "mr_ca682bc6-411b-46e5-88ef-1668032b14d1"
    rule_name = "Impacket WMIExec CISA Report"
    type = "alert"
    data_source = "microsoft sysmon, microsoft windows events"
    tactic = "TA0002"
    technique = "T1047"
    reference = "https://media.defense.gov/2023/May/24/2003229517/-1/-1/0/CSA_Living_off_the_Land.PDF"
    severity = "Medium"
    priority = "Medium"

  events:
    (
        $process.metadata.event_type = "PROCESS_LAUNCH" and
        re.regex($process.target.process.command_line, `1>.*\\ADMIN\$\\__.*2>&1`) nocase
    )
    or
    (
        $process.metadata.event_type = "FILE_CREATION" and
        re.regex($process.target.file.full_path, `\\windows\\__`) nocase
    )
    $process.principal.hostname = $hostname

  match:
    $hostname over 5m

  outcome:
    $risk_score = 65
    // added to populate alert graph with additional context
    $principal_hostname = array_distinct($process.principal.hostname)
    $principal_process_pid = array_distinct($process.principal.process.pid)
    $principal_process_command_line = array_distinct($process.principal.process.command_line)
    $principal_process_file_sha256 = array_distinct($process.principal.process.file.sha256)
    $principal_process_file_full_path = array_distinct($process.principal.process.file.full_path)
    $principal_process_product_specific_process_id = array_distinct($process.principal.process.product_specific_process_id)
    $principal_process_parent_process_product_specific_process_id = array_distinct($process.principal.process.parent_process.product_specific_process_id)
    $target_process_pid = array_distinct($process.target.process.pid)
    $target_process_command_line = array_distinct($process.target.process.command_line)
    $target_process_file_sha256 = array_distinct($process.target.process.file.sha256)
    $target_process_file_full_path = array_distinct($process.target.process.file.full_path)
    $target_process_product_specific_process_id = array_distinct($process.target.process.product_specific_process_id)
    $principal_user_userid = array_distinct($process.principal.user.userid)
    $target_user_userid = array_distinct($process.target.user.userid)
    $target_file_full_path = array_distinct($process.target.file.full_path)

  condition:
    $process
}