Disabled Kerberos Pre-Authentication Discovery With Get-ADUser

SPLUNK detection rule by Mauricio Velazco, Splunk · Apache-2.0

The following analytic detects the execution of the `Get-ADUser` PowerShell cmdlet with parameters indicating a search for domain accounts with Kerberos Pre-Authentication disabled. It leverages PowerShell Script Block Logging (EventCode=4104) to identify this specific activity. This behavior is significant because discovering accounts with Kerberos Pre-Authentication disabled can allow adversaries to perform offline password cracking. If confirmed malicious, this activity could lead to unauthorized access to user accounts, potentially compromising sensitive information and escalating privileges within the network.

name: Disabled Kerberos Pre-Authentication Discovery With Get-ADUser
id: 114c6bfe-9406-11ec-bcce-acde48001122
version: 15
creation_date: '2022-02-18'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: TTP
description: The following analytic detects the execution of the `Get-ADUser` PowerShell cmdlet with parameters indicating a search for domain accounts with Kerberos Pre-Authentication disabled. It leverages PowerShell Script Block Logging (EventCode=4104) to identify this specific activity. This behavior is significant because discovering accounts with Kerberos Pre-Authentication disabled can allow adversaries to perform offline password cracking. If confirmed malicious, this activity could lead to unauthorized access to user accounts, potentially compromising sensitive information and escalating privileges within the network.
data_source:
    - Powershell Script Block Logging 4104
search: |-
    `powershell` EventCode=4104 (ScriptBlockText = "*Get-ADUser*" AND ScriptBlockText="*4194304*")
      | fillnull
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY dest signature signature_id
           user_id vendor_product EventID
           Guid Opcode Name
           Path ProcessID ScriptBlockId
           ScriptBlockText
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `disabled_kerberos_pre_authentication_discovery_with_get_aduser_filter`
how_to_implement: To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba.
known_false_positives: Administrators or power users may use search for accounts with Kerberos Pre Authentication disabled for legitimate purposes.
references:
    - https://attack.mitre.org/techniques/T1558/004/
    - https://m0chan.github.io/2019/07/31/How-To-Attack-Kerberos-101.html
    - https://stealthbits.com/blog/cracking-active-directory-passwords-with-as-rep-roasting/
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: Disabled Kerberos Pre-Authentication Discovery With Get-ADUser from $dest$
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - CISA AA23-347A
    - Active Directory Kerberos Attacks
    - BlackSuit Ransomware
    - Interlock Ransomware
asset_type: Endpoint
mitre_attack_id:
    - T1558.004
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1558.004/getaduser/get-aduser-powershell.log
          source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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