Windows Get-AdComputer Unconstrained Delegation Discovery

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Description

The following analytic detects the use of the Get-ADComputer cmdlet with parameters indicating a search for Windows endpoints with Kerberos Unconstrained Delegation. It leverages PowerShell Script Block Logging (EventCode=4104) to identify this specific activity. This behavior is significant as it may indicate an attempt by adversaries or Red Teams to gain situational awareness and perform Active Directory discovery. If confirmed malicious, this activity could allow attackers to identify high-value targets for further exploitation, potentially leading to privilege escalation or lateral movement within the network.

• Type: TTP

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

• Last Updated: 2024-05-13
• Author: Mauricio Velazco, Splunk
• ID: c8640777-469f-4638-ab44-c34a3233ffac

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1018	Remote System Discovery	Discovery

Kill Chain Phase

• Exploitation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

 `powershell` EventCode=4104 (ScriptBlockText = "*Get-ADComputer*" AND ScriptBlockText = "*TrustedForDelegation*") 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID 
| rename Computer as dest 
| rename UserID as user 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_get_adcomputer_unconstrained_delegation_discovery_filter`

Macros

The SPL above uses the following Macros:

• powershell
• security_content_ctime

windows_get-adcomputer_unconstrained_delegation_discovery_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
• ScriptBlockText
• Computer
• UserID

How To Implement

The following analytic requires PowerShell operational logs to be imported. Modify the powershell macro as needed to match the sourcetype or add index. This analytic is specific to 4104, or PowerShell Script Block Logging.

Known False Positives

Administrators or power users may leverage PowerView for system management or troubleshooting.

Associated Analytic Story

• Active Directory Kerberos Attacks

RBA

Risk Score	Impact	Confidence	Message
35.0	50	70	Suspicious PowerShell Get-ADComputer was identified on endpoint $dest$

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

• https://attack.mitre.org/techniques/T1018/
• https://adsecurity.org/?p=1667
• https://docs.microsoft.com/en-us/defender-for-identity/cas-isp-unconstrained-kerberos
• https://www.ired.team/offensive-security-experiments/active-directory-kerberos-abuse/domain-compromise-via-unrestricted-kerberos-delegation
• https://www.cyberark.com/resources/threat-research-blog/weakness-within-kerberos-delegation

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

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