Detection rules › Splunk
GetAdComputer with PowerShell Script Block
The following analytic detects the execution of the Get-AdComputer PowerShell commandlet using PowerShell Script Block Logging (EventCode=4104). This detection leverages script block text to identify when this commandlet is run. The Get-AdComputer commandlet is significant as it can be used by adversaries to enumerate all domain computers, aiding in situational awareness and Active Directory discovery. If confirmed malicious, this activity could allow attackers to map the network, identify targets, and plan further attacks, potentially leading to unauthorized access and data exfiltration.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Discovery | T1018 Remote System Discovery |
Event coverage
| Provider | Event | Title |
|---|---|---|
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
Rule body splunk
name: GetAdComputer with PowerShell Script Block
id: a9a1da02-8e27-4bf7-a348-f4389c9da487
version: 11
creation_date: '2021-09-01'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: Hunting
description: The following analytic detects the execution of the `Get-AdComputer` PowerShell commandlet using PowerShell Script Block Logging (EventCode=4104). This detection leverages script block text to identify when this commandlet is run. The `Get-AdComputer` commandlet is significant as it can be used by adversaries to enumerate all domain computers, aiding in situational awareness and Active Directory discovery. If confirmed malicious, this activity could allow attackers to map the network, identify targets, and plan further attacks, potentially leading to unauthorized access and data exfiltration.
data_source:
- Powershell Script Block Logging 4104
search: |-
`powershell` EventCode=4104 (ScriptBlockText = "*Get-AdComputer*")
| 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)`
| `getadcomputer_with_powershell_script_block_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 this PowerShell commandlet for troubleshooting.
references:
- https://attack.mitre.org/techniques/T1018/
- https://docs.microsoft.com/en-us/powershell/module/activedirectory/get-adgroup?view=windowsserver2019-ps
analytic_story:
- Active Directory Discovery
- CISA AA22-320A
- Medusa Ransomware
- Gozi Malware
asset_type: Endpoint
mitre_attack_id:
- T1018
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/T1059.001/powershell_script_block_logging/sbl_xml.log
source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
sourcetype: XmlWinEventLog
test_type: unit
Stages and Predicates
Stage 1: search
`powershell` EventCode=4104 (ScriptBlockText = "*Get-AdComputer*")
Stage 2: fillnull
| fillnull
Stage 3: stats
| 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
Stage 4: search
| `security_content_ctime(firstTime)`
Stage 5: search
| `getadcomputer_with_powershell_script_block_filter`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
ScriptBlockText | eq |
|