Detection: Windows NorthStar C2 Agent Execution

Description

Detects the initial agent or persistent agent processes for Northstar C2 being run. NorthStarC2 is an open-source command and control framework developed for penetration testing and red teaming purposes by Engin Demirbilek. NorthStar C2 Framework consists of two applications, a server-side GUI web application for managing sessions and a client-side stager to communicate with C2 server.

Search

 1
 2| tstats `security_content_summariesonly`
 3  count min(_time) as firstTime
 4        max(_time) as lastTime
 5
 6from datamodel=Endpoint.Processes where
 7
 8Processes.original_file_name="NorthstarStager.exe"
 9OR
10Processes.process_name IN (
11    "NorthstarStager.exe",
12    "SystemHealthCheck.exe"
13)
14
15by Processes.process Processes.vendor_product Processes.user_id Processes.process_hash
16   Processes.parent_process_name Processes.parent_process_exec Processes.action
17   Processes.dest Processes.process_current_directory Processes.process_path
18   Processes.process_integrity_level Processes.original_file_name Processes.parent_process
19   Processes.parent_process_path Processes.parent_process_guid Processes.parent_process_id
20   Processes.process_guid Processes.process_id Processes.user Processes.process_name
21
22
23| `drop_dm_object_name(Processes)`
24
25| `security_content_ctime(firstTime)`
26
27| `security_content_ctime(lastTime)`
28
29| `windows_northstar_c2_agent_execution_filter`

Data Source

Name	Platform	Sourcetype	Source
CrowdStrike ProcessRollup2	Other	'crowdstrike:events:sensor'	'crowdstrike'
Sysmon EventID 1	Windows	'XmlWinEventLog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Windows Event Log Security 4688	Windows	'XmlWinEventLog'	'XmlWinEventLog:Security'

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

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

Some legitimate red team or penetration testing activities may use Northstar C2 agents. Filter alerts when these tools are approved for authorized testing.

Associated Analytic Story

• Compromised Windows Host

Risk Based Analytics (RBA)

Risk Message:

NorthStar C2 agent execution observed on $dest$ via $process$.

References

• https://github.com/EnginDemirbilek/NorthStarC2/

Detection Testing

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: 1