Detection: Windows Netspy Network Scanner Execution

Description

Detects usage of the Netspy scanner on an endpoint. Netspy is a lightweight, fast, and cross-platform tool designed for internal network segment discovery. The tool supports various protocols, including ICMP, ARP, TCP, and UDP, allowing users to scan for active hosts and services within predefined IP ranges.

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.process_name="netspy.exe"
 9Processes.process IN (
10    "*arpspy*",
11    "*as*",
12    "*icmpspy*",
13    "*is*",
14    "*pingspy*",
15    "*ps*",
16    "*tcpspy*",
17    "*ts*",
18    "*udpspy*",
19    "*us*"
20)
21
22by Processes.process Processes.process_name Processes.user_id Processes.process_hash
23   Processes.parent_process_name Processes.parent_process_exec Processes.action
24   Processes.dest Processes.process_current_directory Processes.process_path
25   Processes.process_integrity_level Processes.original_file_name Processes.parent_process
26   Processes.parent_process_path Processes.parent_process_guid Processes.parent_process_id
27   Processes.process_guid Processes.process_id Processes.user Processes.vendor_product
28
29
30| `drop_dm_object_name(Processes)`
31
32| `security_content_ctime(firstTime)`
33
34| `security_content_ctime(lastTime)`
35
36| `windows_netspy_network_scanner_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

Legitimate network administrators may use Netspy for authorized network discovery and maintenance. Filter alerts for approved internal network scanning activities.

Associated Analytic Story

• Network Discovery

• Windows Discovery Techniques

Risk Based Analytics (RBA)

Risk Message:

Potential Netspy Network Scanner activity observed on $dest$ via $process$.

References

• https://www.securonix.com/blog/from-cobalt-strike-to-mimikatz-slowtempest/

• https://github.com/shmilylty/netspy

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