ID | Technique | Tactic |
---|---|---|
T1135 | Network Share Discovery | Discovery |
Detection: Windows File Share Discovery With Powerview
Description
The following analytic detects the execution of the Invoke-ShareFinder PowerShell cmdlet from PowerView. This detection leverages PowerShell Script Block Logging to identify instances where this specific command is executed. Monitoring this activity is crucial as it indicates an attempt to enumerate network file shares, which may contain sensitive information such as backups, scripts, and credentials. If confirmed malicious, this activity could enable an attacker to escalate privileges or move laterally within the network, potentially compromising additional systems and sensitive data.
Search
1`powershell` EventCode=4104 (ScriptBlockText=Invoke-ShareFinder*)
2| stats count min(_time) as firstTime max(_time) as lastTime by Opcode Computer UserID EventCode ScriptBlockText
3| `security_content_ctime(firstTime)`
4| `security_content_ctime(lastTime)`
5| `windows_file_share_discovery_with_powerview_filter`
Data Source
Name | Platform | Sourcetype | Source |
---|---|---|---|
Powershell Script Block Logging 4104 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Microsoft-Windows-PowerShell/Operational' |
Macros Used
Name | Value |
---|---|
powershell | (source=WinEventLog:Microsoft-Windows-PowerShell/Operational OR source="XmlWinEventLog:Microsoft-Windows-PowerShell/Operational") |
windows_file_share_discovery_with_powerview_filter | search * |
windows_file_share_discovery_with_powerview_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.=
Known False Positives
Security teams may leverage PowerView proactively to identify and remediate sensitive file shares. Filter as needed.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
Invoke-ShareFinder commandlet was executed on $Computer$ | 48 | 60 | 80 |
References
-
https://github.com/PowerShellEmpire/PowerTools/blob/master/PowerView/powerview.ps1
-
https://thedfirreport.com/2023/01/23/sharefinder-how-threat-actors-discover-file-shares/
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: 3