Windows File Share Discovery With Powerview
Description
The following analytic identifies the use of the Invoke-ShareFinder PowerShell commandlet part of PowerView. This module obtains the list of all active domain computers and lists the active shares on each computer. Network file shares in Active Directory environments may contain sensitive information like backups, scripts, credentials, etc. Adversaries who have obtained a foothold in an AD network may leverage PowerView to identify secrets and leverage them for Privilege Escalation or Lateral Movement.
- Type: TTP
-
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2023-03-20
- Author: Mauricio Velazco, Splunk
- ID: a44c0be1-d7ab-41e4-92fd-aa9af4fe232c
Annotations
Kill Chain Phase
- Exploitation
NIST
- DE.CM
CIS20
- CIS 10
CVE
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`powershell` EventCode=4104 (ScriptBlockText=Invoke-ShareFinder*)
| stats count min(_time) as firstTime max(_time) as lastTime by Opcode Computer UserID EventCode ScriptBlockText
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_file_share_discovery_with_powerview_filter`
Macros
The SPL above uses the following Macros:
windows_file_share_discovery_with_powerview_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
- Opcode
- Computer
- UserID
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://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
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
48.0 | 60 | 80 | Invoke-ShareFinder commandlet was executed on $Computer$ |
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://github.com/PowerShellEmpire/PowerTools/blob/master/PowerView/powerview.ps1
- https://thedfirreport.com/2023/01/23/sharefinder-how-threat-actors-discover-file-shares/
- https://attack.mitre.org/techniques/T1135/
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: 1