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Description

The following analytic identifies when either a global catalog SPN or a DRS RPC SPN are temporarily added to an Active Directory computer object, both of which can be evidence of a DCShadow attack. DCShadow allows an attacker who has obtained privileged access to register a rogue Domain Controller (DC). Once registered, the rogue DC may be able to inject and replicate changes into the AD infrastructure for any domain object, including credentials and keys. This technique was initially released in 2018 by security researchers Benjamin Delpy and Vincent Le Toux. No event logs are written for changes to AD attributes, allowing for stealthy backdoors to be implanted in the domain, or metadata such as timestamps overwritten to cover tracks.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2022-09-02
  • Author: Dean Luxton
  • ID: 57e27f27-369c-4df8-af08-e8c7ee8373d4

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1207 Rogue Domain Controller Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`wineventlog_security` EventCode=5136 AttributeLDAPDisplayName=servicePrincipalName (AttributeValue="GC/*" OR AttributeValue="E3514235-4B06-11D1-AB04-00C04FC2DCD2/*") 
| stats min(_time) as _time range(_time) as duration values(OperationType) as OperationType values(src_nt_domain) as src_nt_domain values(src_user) as src_user values(Computer) as Computer, values(ObjectDN) as ObjectDN by Logon_ID 
| eval short_lived=case((duration<30),"TRUE") 
| where short_lived="TRUE" AND mvcount(OperationType)>1 
| replace "%%14674" with "Value Added", "%%14675" with "Value Deleted" in OperationType 
| rename Logon_ID as TargetLogonId 
| appendpipe [
| map search="search `wineventlog_security` EventCode=4624 TargetLogonId=$TargetLogonId$"] 
| stats min(_time) as _time, values(TargetUserSid) as TargetUserSid, values(Target_Domain) as Target_Domain, values(user) as user, values(Computer) as Computer, values(status) as status, values(src_category) as src_category, values(src_ip) as src_ip values(ObjectDN) as ObjectDN values(OperationType) as OperationType by TargetLogonId 
| `windows_ad_short_lived_domain_controller_spn_attribute_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_ad_short_lived_domain_controller_spn_attribute_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • EventCode
  • AttributeLDAPDisplayName
  • AttributeValue
  • src_nt_domain
  • src_user
  • Computer
  • ObjectDN
  • Logon_ID
  • signature

How To Implement

To successfully implement this search, you need to be ingesting eventcode 5136. The Advanced Security Audit policy setting Audit Directory Services Changes within DS Access needs to be enabled, alongside a SACL for everybody to Write All Properties applied to the domain root and all descendant objects.

Known False Positives

None.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
100.0 100 100 Short Lived Domain Controller SPN AD Attribute Triggered by $user$ from $src_ip$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 2