Windows Computer Account Created by Computer Account

Description

The following analytic identifies a computer account creating a new computer account with a specific Service Principal Name (SPN) "RestrictedKrbHost". This detection leverages Windows Security Event Logs, specifically EventCode 4741, to identify such activities. This behavior is significant as it may indicate an attempt to establish unauthorized Kerberos authentication channels, potentially leading to lateral movement or privilege escalation. If confirmed malicious, this activity could allow an attacker to impersonate services, access sensitive information, or maintain persistence within the network.

Query · spl

`wineventlog_security` EventCode=4741 user_type=computer SubjectDomainName!="NT AUTHORITY" ServicePrincipalNames=*RestrictedKrbHost*
  | stats  count min(_time) as firstTime max(_time) as lastTime
    BY dest, subject, action
       ,src_user, user, user_type,
       SubjectUserName,SubjectDomainName
  | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)`
  | `windows_computer_account_created_by_computer_account_filter`

Implementation guide

To successfully implement this search, you need to be ingesting Windows Security Event Logs with 4741 EventCode enabled. The Windows TA is also required.

Known false positives

  • It is possible third party applications may have a computer account that adds computer accounts, filtering may be required.

Analyst notes

Known false positives: It is possible third party applications may have a computer account that adds computer accounts, filtering may be required.

Raw source Windows Computer Account Created by Computer Account · SPL
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Published by splunk/security_content ↗, licensed under Apache 2.0 ↗. Reproduced here unmodified. 
name: Windows Computer Account Created by Computer Account
id: 97a8dc5f-8a7c-4fed-9e3e-ec407fd0268a
version: 10
creation_date: '2022-04-28'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies a computer account creating a new computer account with a specific Service Principal Name (SPN) "RestrictedKrbHost". This detection leverages Windows Security Event Logs, specifically EventCode 4741, to identify such activities. This behavior is significant as it may indicate an attempt to establish unauthorized Kerberos authentication channels, potentially leading to lateral movement or privilege escalation. If confirmed malicious, this activity could allow an attacker to impersonate services, access sensitive information, or maintain persistence within the network.
data_source:
    - Windows Event Log Security 4741
search: |-
    `wineventlog_security` EventCode=4741 user_type=computer SubjectDomainName!="NT AUTHORITY" ServicePrincipalNames=*RestrictedKrbHost*
      | stats  count min(_time) as firstTime max(_time) as lastTime
        BY dest, subject, action
           ,src_user, user, user_type,
           SubjectUserName,SubjectDomainName
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `windows_computer_account_created_by_computer_account_filter`
how_to_implement: To successfully implement this search, you need to be ingesting Windows Security Event Logs with 4741 EventCode enabled. The Windows TA is also required.
known_false_positives: It is possible third party applications may have a computer account that adds computer accounts, filtering may be required.
references:
    - https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-kile/445e4499-7e49-4f2a-8d82-aaf2d1ee3c47
    - https://github.com/Dec0ne/KrbRelayUp
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: A Computer Account on $dest$ created by a computer account (possibly indicative of Kerberos relay attack).
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Active Directory Kerberos Attacks
    - Local Privilege Escalation With KrbRelayUp
asset_type: Endpoint
mitre_attack_id:
    - T1558
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/windows_computer_account_created_by_computer_account/windows-xml.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog
      test_type: unit

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