ID | Technique | Tactic |
---|---|---|
T1059.001 | PowerShell | Execution |
T1059 | Command and Scripting Interpreter | Execution |
Detection: PowerShell - Connect To Internet With Hidden Window
Description
The following analytic detects PowerShell commands using the WindowStyle parameter to hide the window while connecting to the Internet. This behavior is identified through Endpoint Detection and Response (EDR) telemetry, focusing on command-line executions that include variations of the WindowStyle parameter. This activity is significant because it attempts to bypass default PowerShell execution policies and conceal its actions, which is often indicative of malicious intent. If confirmed malicious, this could allow an attacker to execute commands stealthily, potentially leading to unauthorized data exfiltration or further compromise of the endpoint.
Search
1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_powershell` by Processes.user Processes.process_name Processes.process Processes.parent_process_name Processes.original_file_name Processes.dest Processes.process_id
3| `drop_dm_object_name(Processes)`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| where match(process,"(?i)[\-
7|\/
8|–
9|—
10|―]w(in*d*o*w*s*t*y*l*e*)*\s+[^-]")
11| `powershell___connect_to_internet_with_hidden_window_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
CrowdStrike ProcessRollup2 | N/A | 'crowdstrike:events:sensor' |
'crowdstrike' |
N/A |
Macros Used
Name | Value |
---|---|
process_powershell | (Processes.process_name=pwsh.exe OR Processes.process_name=sqlps.exe OR Processes.process_name=sqltoolsps.exe OR Processes.process_name=powershell.exe OR Processes.process_name=powershell_ise.exe OR Processes.original_file_name=pwsh.dll OR Processes.original_file_name=PowerShell.EXE OR Processes.original_file_name=powershell_ise.EXE) |
powershell___connect_to_internet_with_hidden_window_filter | search * |
powershell___connect_to_internet_with_hidden_window_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 Risk Event | False |
Implementation
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes
node of the Endpoint
data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
Known False Positives
Legitimate process can have this combination of command-line options, but it's not common.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
PowerShell processes $process$ started with parameters to modify the execution policy of the run, run in a hidden window, and connect to the Internet on host $dest$ executed by user $user$. | 81 | 90 | 90 |
References
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
xmlwineventlog |
Integration | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-Sysmon/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: 9