printbrm_zip_creation_or_extraction

rule printbrm_zip_creation_or_extraction {

  meta:
    author = "frack113"
    description = "Detects the execution of the LOLBIN PrintBrm.exe, which can be used to create or extract ZIP files. PrintBrm.exe should not be run on a normal workstation"
    reference = "https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_lolbin_printbrm.yml"
    license = "https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md"
    rule_name = "PrintBrm ZIP Creation of Extraction"
    sigma_uuid = "cafeeba3-01da-4ab4-b6c4-a31b1d9730c7"
    sigma_status = "test"
    rule_id = "mr_3d3036d7-f2f8-4037-ab33-f4cef1e1f4b5"
    tactic = "TA0011"
    technique = "T1105"
    type = "Detection"
    data_source = "Windows Event Logs"
    platform = "Windows"
    severity = "High"
    priority = "High"
    false_positives = "Unknown"

  events:
    $process.metadata.event_type = "PROCESS_LAUNCH"
    re.regex($process.target.process.file.full_path, `\\PrintBrm\.exe$`) nocase
    (
        strings.contains(strings.to_lower($process.target.process.command_line), " -f") and
        strings.contains(strings.to_lower($process.target.process.command_line), ".zip")
    )
    $process.principal.hostname = $hostname

  match:
    $hostname over 5m

  outcome:
    //example usage of specifying test user and hostname to adjust risk score
    $risk_score = max(if($process.principal.user.userid = "user" and $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)
    $principal_user_userid = array_distinct($process.principal.user.userid)
    $log_type = array_distinct(strings.concat($process.metadata.log_type,"/",$process.metadata.product_event_type))

  condition:
    $process
}