Nishang PowershellTCPOneLine
Description
This query detects the Nishang Invoke-PowerShellTCPOneLine utility that spawns a call back to a remote Command And Control server. This is a powershell oneliner. In addition, this will capture on the command-line additional utilities used by Nishang. Triage the endpoint and identify any parallel processes that look suspicious. Review the reputation of the remote IP or domain contacted by the powershell process.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2021-03-03
- Author: Michael Haag, Splunk
- ID: 1a382c6c-7c2e-11eb-ac69-acde48001122
Annotations
ATT&CK
Kill Chain Phase
- Installation
NIST
- DE.CM
CIS20
- CIS 10
CVE
Search
1
2
3
4
5
6
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_powershell` (Processes.process=*Net.Sockets.TCPClient* AND Processes.process=*System.Text.ASCIIEncoding*) by Processes.dest Processes.user Processes.parent_process Processes.original_file_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `nishang_powershelltcponeline_filter`
Macros
The SPL above uses the following Macros:
nishang_powershelltcponeline_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
- Processes.dest
- Processes.user
- Processes.parent_process_name
- Processes.parent_process
- Processes.original_file_name
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_path
- Processes.process_path
- Processes.parent_process_id
How To Implement
To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
Known False Positives
Limited false positives may be present. Filter as needed based on initial analysis.
Associated Analytic Story
RBA
| Risk Score | Impact | Confidence | Message |
|---|---|---|---|
| 42.0 | 70 | 60 | Possible Nishang Invoke-PowerShellTCPOneLine behavior on $dest$ |
Reference
- https://github.com/samratashok/nishang/blob/master/Shells/Invoke-PowerShellTcpOneLine.ps1
- https://www.volexity.com/blog/2021/03/02/active-exploitation-of-microsoft-exchange-zero-day-vulnerabilities/
- https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/
- https://www.rapid7.com/blog/post/2021/03/03/rapid7s-insightidr-enables-detection-and-response-to-microsoft-exchange-0-day/
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: 2