MITRE ATT&CK T1033 Recon Successful Logon Enumeration Powershell CISA Report

// Copyright 2023 Google LLC. Licensed under Apache-2.0.

rule recon_successful_logon_enumeration_powershell_T1033_cisa_report {

  meta:
    author = "Google Cloud Security"
    description = "Detects the use of powershell to enumerate successful logins on a specific host"
    rule_id = "mr_db589a2e-0a06-46b5-8479-f8e120ec0405"
    rule_name = "MITRE ATT&CK T1033 Recon Successful Logon Enumeration Powershell CISA Report"
    type = "hunt"
    platform = "Windows"
    data_source = "microsoft sysmon"
    tactic = "TA0007"
    mitre_attack_technique = "T1033"
    reference = "https://media.defense.gov/2023/May/24/2003229517/-1/-1/0/CSA_Living_off_the_Land.PDF"
    severity = "Info"
    priority = "Info"

  events:
    (
        $process.metadata.event_type = "PROCESS_LAUNCH" and
        // cisa report referenced cmd /c and other wmic switches like /user and /password, these have been excluded to focus on the commands being issued since
        // focused on event code 4624 but could be modified to look for other event codes if needed
        re.regex($process.target.process.command_line, `(|cmd.*/c).*Get-EventLog.*security.*-instanceid.*4624`) nocase
    )
    or
    (
        $process.metadata.event_type = "STATUS_UPDATE" and
        re.regex($process.security_result.description, `Get-EventLog.*security.*-instanceid.*4624`) nocase
    )
    $process.principal.hostname = $hostname

  match:
    $hostname over 15m

  outcome:
    $risk_score = 15
    $event_count = count_distinct($process.metadata.id)
    $security_result_description = array_distinct($process.security_result.description)
    // added to populate alert graph with additional context
    // Commented out principal.hostname because it is already represented in graph as match variable. If match changes, can uncomment to add to results
    //$principal_hostname = array_distinct($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)

  condition:
    $process
}