splunk-security_content/docs/_posts/2020-07-21-prohibited_network_traffic_allowed.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Prohibited Network Traffic Allowed	Exfiltration Over Alternative Protocol	Network	2020-07-21	true		Exfiltration Over Alternative Protocol Exfiltration Splunk Enterprise Splunk Enterprise Security Splunk Cloud Network_Traffic

⚠️ WARNING THIS IS A EXPERIMENTAL DETECTION

We have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.

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Description

This search looks for network traffic defined by port and transport layer protocol in the Enterprise Security lookup table "lookup_interesting_ports", that is marked as prohibited, and has an associated 'allow' action in the Network_Traffic data model. This could be indicative of a misconfigured network device.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Network_Traffic
• Last Updated: 2020-07-21
• Author: Rico Valdez, Splunk
• ID: ce5a0962-849f-4720-a678-753fe6674479

ATT&CK

ID	Technique	Tactic
T1048	Exfiltration Over Alternative Protocol	Exfiltration

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Network_Traffic where All_Traffic.action = allowed by All_Traffic.src_ip All_Traffic.dest_ip All_Traffic.dest_port All_Traffic.action 
| lookup update=true interesting_ports_lookup dest_port as All_Traffic.dest_port OUTPUT app is_prohibited note transport 
| search is_prohibited=true 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `drop_dm_object_name("All_Traffic")` 
| `prohibited_network_traffic_allowed_filter`

Associated Analytic Story

• Prohibited Traffic Allowed or Protocol Mismatch
• Ransomware
• Command and Control

How To Implement

In order to properly run this search, Splunk needs to ingest data from firewalls or other network control devices that mediate the traffic allowed into an environment. This is necessary so that the search can identify an 'action' taken on the traffic of interest. The search requires the Network_Traffic data model be populated.

Required field

• _time
• All_Traffic.action
• All_Traffic.src_ip
• All_Traffic.dest_ip
• All_Traffic.dest_port

Kill Chain Phase

• Delivery
• Command and Control

Known False Positives

None identified

Reference

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

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