Network Connection Discovery With Arp

Try in Splunk Security Cloud

Description

This analytic looks for the execution of arp.exe utilized to get a listing of network connections on a compromised system. Red Teams and adversaries alike may use arp.exe for situational awareness and Active Directory Discovery.

• Type: Hunting
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-09-10
• Author: Mauricio Velazco, Splunk
• ID: ae008c0f-83bd-4ed4-9350-98d4328e15d2

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1049	System Network Connections Discovery	Discovery

Kill Chain Phase

• Exploitation

NIST

• DE.AE

CIS20

• CIS 10

CVE

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name="arp.exe") (Processes.process=*-a*) by Processes.dest Processes.user Processes.parent_process 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)` 
| `network_connection_discovery_with_arp_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• security_content_summariesonly

network_connection_discovery_with_arp_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.

• 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.

Known False Positives

Administrators or power users may use this command for troubleshooting.

Associated Analytic Story

• Active Directory Discovery
• Qakbot
• Windows Post-Exploitation
• Prestige Ransomware
• Volt Typhoon
• IcedID

RBA

Risk Score	Impact	Confidence	Message
15.0	30	50	Network Connection discovery on $dest$ by $user$

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://attack.mitre.org/techniques/T1049/
• https://www.microsoft.com/en-us/security/blog/2023/05/24/volt-typhoon-targets-us-critical-infrastructure-with-living-off-the-land-techniques/
• https://thedfirreport.com/2023/05/22/icedid-macro-ends-in-nokoyawa-ransomware/

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