Detection: Get DomainUser with PowerShell Script Block
Description
The following analytic detects the execution of the Get-DomainUser cmdlet using PowerShell Script Block Logging (EventCode=4104). This cmdlet is part of PowerView, a tool often used for domain enumeration. The detection leverages PowerShell operational logs to identify instances where this command is executed. Monitoring this activity is crucial as it may indicate an adversary's attempt to gather information about domain users, which is a common step in Active Directory Discovery. If confirmed malicious, this activity could lead to further reconnaissance and potential exploitation of domain resources.
Search
1`powershell` EventCode=4104 ScriptBlockText = "*Get-DomainUser*"
2
3| fillnull
4
5| stats count min(_time) as firstTime max(_time) as lastTime
6 BY dest signature signature_id
7 user_id vendor_product EventID
8 Guid Opcode Name
9 Path ProcessID ScriptBlockId
10 ScriptBlockText
11
12| `security_content_ctime(firstTime)`
13
14| `security_content_ctime(lastTime)`
15
16| `get_domainuser_with_powershell_script_block_filter`
Data Source
Macros Used
| Name |
Value |
| security_content_ctime |
convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$) |
| get_domainuser_with_powershell_script_block_filter |
search * |
get_domainuser_with_powershell_script_block_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
| ID |
Technique |
Tactic |
| T1087.002 |
Domain Account |
Discovery |
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
| Setting |
Value |
| Disabled |
true |
| Cron Schedule |
0 * * * * |
| Earliest Time |
-70m@m |
| Latest Time |
-10m@m |
| Schedule Window |
auto |
| Creates Finding (Notable) |
Yes |
| Rule Title |
%name% |
| Rule Description |
%description% |
| Notable Event Fields |
user, dest |
| Creates Intermediate Finding (Risk Event) |
Yes |
TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.
Implementation
The following Hunting 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 use this command for troubleshooting.
Associated Analytic Story
Finding
| Title |
Entity Field |
Entity Type |
Risk Score |
| Powershell process having commandline "Get-DomainUser" for user enumeration on $dest$ |
user_id |
user |
50 |
| Message |
Entity Field |
Entity Type |
Risk Score |
| Powershell process having commandline "Get-DomainUser" for user enumeration on $dest$ |
dest |
system |
50 |
References
Detection Testing
| Test Type |
Status |
Dataset |
Source |
Sourcetype |
| Validation |
✅ Passing |
N/A |
N/A |
N/A |
| Unit |
✅ Passing |
Dataset |
XmlWinEventLog:Microsoft-Windows-PowerShell/Operational |
XmlWinEventLog |
| Integration |
✅ Passing |
Dataset |
XmlWinEventLog:Microsoft-Windows-PowerShell/Operational |
XmlWinEventLog |
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: GitHub |
Version: 13