Detection: Get DNS traffic ratio

REMOVED DETECTION

This detection has been removed from the Splunk Threat Research content library and is no longer maintained or supported.

Reason: As of Splunk Enterprise Security version 8.0, Splunk Enterprise Security no longer supports Investigations. As such, all Investigations have been deprecated in ES Content Update.

Removed in version: 5.2.0

If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2026-05-13 ID: bc91a8cf-35e7-4bb2-8140-e756cc06fd73 Author: Bhavin Patel, Splunk Type: Investigation Product: Splunk Enterprise Security

Description

This search calculates the ratio of DNS traffic originating and coming from a host to a list of DNS servers over the last 24 hours. A high value of this ratio could be very useful to quickly understand if a src_ip (host) is sending a high volume of data out via port 53, could be an indicator of data exfiltration via DNS.

Search

1
2| tstats allow_old_summaries=true sum(All_Traffic.bytes_out) as "bytes_out" sum(All_Traffic.bytes_in) as "bytes_in" from datamodel=Network_Traffic where nodename=All_Traffic All_Traffic.dest_port=53 by All_Traffic.src All_Traffic.dest
3| `drop_dm_object_name(All_Traffic)` 
4| rename src as src_ip 
5| rename dest as dest_ip 
6| search src_ip=$src_ip$ 
7| search dest_ip = $dest_ip 
8| eval ratio = (bytes_out/bytes_in) 
9| table ratio

Data Source

No data sources specified for this detection.

Macros Used

Name	Value
drop_dm_object_name	``

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic

Default Configuration

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

Setting	Value
Disabled	true
Cron Schedule	`N/A`
Earliest Time	`N/A`
Latest Time	`N/A`
Schedule Window	`N/A`
Creates Finding (Notable)	No
Creates Intermediate Finding (Risk Event)	No

Implementation

You must be ingesting your network traffic

Known False Positives

Associated Analytic Story

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	Not Applicable	N/A	N/A	N/A
Unit	Not Applicable	N/A	`N/A`	`N/A`
Integration	Not Applicable	N/A	`N/A`	`N/A`

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: 2