LSASS Memory Access by Tool With Dump Keyword In Name

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 * 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 lsass_memory_access_by_tool_dump_keyword_name {

  meta:
    author = "Florian Roth (Nextron Systems)"
    description = "Detects LSASS process access requests from a source process with the dump keyword in its image name"
    reference = "https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_access/proc_access_win_lsass_dump_keyword_image.yml"
    license = "https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md"
    rule_name = "LSASS Memory Access by Tool With Dump Keyword In Name"
    sigma_uuid = "9bd012ee-0dff-44d7-84a0-aa698cfd87a3"
    sigma_status = "test"
    rule_id = "mr_98164cc1-0051-49c1-b915-421b3c119bfe"
    tactic = "TA0006"
    technique = "T1003.001"
    type = "Detection"
    data_source = "Sysmon"
    platform = "Windows"
    severity = "High"
    priority = "High"
    false_positives = "Rare programs that contain the word dump in their name and access lsass"

  events:
    $process.metadata.event_type = "PROCESS_OPEN"
    re.regex($process.target.process.file.full_path, `\\lsass.exe$`) nocase
    strings.contains(strings.to_lower($process.principal.process.file.full_path), "dump")
    re.regex($process.target.resource.name, `(10|30|50|70|90|B0|D0|F0|18|38|58|78|98|B8|D8|F8|1A|3A|5A|7A|9A|BA|DA|FA|0x14C2|FF)$`) nocase

    $process.principal.hostname = $hostname

  match:
    $hostname over 5m

  outcome:
    //example usage of specifying test hostname to adjust risk score
    $risk_score = max(if($process.principal.hostname = "hostname", 0, 15))
    $principal_process_pid = array_distinct($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)
    $principal_process_product_specfic_process_id = array_distinct($process.principal.process.product_specific_process_id)
    $principal_process_parent_process_product_specfic_process_id = array_distinct($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)
    $target_process_product_specfic_process_id = array_distinct($process.target.process.product_specific_process_id)
    $log_type = array_distinct(strings.concat($process.metadata.log_type,"/",$process.metadata.product_event_type))

  condition:
    $process
}