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 analytic

We have not been able to test, simulate, or build datasets for this object. 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

Annotations

ATT&CK

ID	Technique	Tactic
T1048	Exfiltration Over Alternative Protocol	Exfiltration

Kill Chain Phase

• Delivery
• Command & Control

NIST

• DE.AE
• PR.AC

CIS20

• CIS 9
• CIS 12

CVE

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`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• security_content_summariesonly

ℹ️ prohibited_network_traffic_allowed_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

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

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.

Known False Positives

None identified

Associated Analytic story

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

RBA

Risk Score	Impact	Confidence	Message
25.0	50	50	tbd

ℹ️ 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

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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