DNS Query Requests Resolved by Unauthorized DNS Servers

Description

This search will detect DNS requests resolved by unauthorized DNS servers. Legitimate DNS servers should be identified in the Enterprise Security Assets and Identity Framework.

Type: TTP
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
Datamodel: Network_Resolution
Last Updated: 2020-07-21
Author: Bhavin Patel, Splunk
ID: 1a67f15a-f4ff-4170-84e9-08cf6f75d6f6

Annotations

ATT&CK

ID	Technique	Tactic
T1071.004	DNS	Command And Control

Kill Chain Phase

Command & Control

NIST

ID.AM
PR.DS
PR.IP
DE.AE
DE.CM

CIS20

CIS 1
CIS 3
CIS 8
CIS 12

CVE

Search

| tstats `security_content_summariesonly` count from datamodel=Network_Resolution where DNS.dest_category != dns_server AND DNS.src_category != dns_server by DNS.src DNS.dest 
| `drop_dm_object_name("DNS")` 
| `dns_query_requests_resolved_by_unauthorized_dns_servers_filter` 

Macros

The SPL above uses the following Macros:

security_content_summariesonly

Note that dns_query_requests_resolved_by_unauthorized_dns_servers_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
DNS.dest_category
DNS.src_category
DNS.src
DNS.dest

How To Implement

To successfully implement this search you will need to ensure that DNS data is populating the Network_Resolution data model. It also requires that your DNS servers are identified correctly in the Assets and Identity table of Enterprise Security.

Known False Positives

Legitimate DNS activity can be detected in this search. Investigate, verify and update the list of authorized DNS servers as appropriate.

Associated Analytic story

RBA

Risk Score	Impact	Confidence	Message
25.0	50	50	tbd

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

source | version: 3

Twitter Facebook LinkedIn