Detection: Detect Remote Access Software Usage DNS

Created: 2024-03-06 Last Updated: 2026-10-08 ID: a16b797d-e309-41bd-8ba0-5067dae2e4be Author: Steven Dick, Onur Mustafa Erdogan, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic detects DNS queries to domains associated with known remote access software such as AnyDesk, GoToMyPC, LogMeIn, and TeamViewer.

Search

 1
 2| tstats `security_content_summariesonly`
 3  count min(_time) as firstTime
 4        max(_time) as lastTime
 5
 6FROM datamodel=Network_Resolution WHERE
 7
 8[
 9    
10| inputlookup remote_access_software
11    
12| search domain!=""
13    
14| rename domain as DNS.query
15    
16| table DNS.query
17]
18
19BY DNS.answer DNS.answer_count DNS.query
20   DNS.query_count DNS.reply_code_id DNS.src
21   DNS.vendor_product
22
23
24| `drop_dm_object_name("DNS")`
25
26
27| lookup local=t remote_access_software domain AS query OUTPUT app as signature, category, reference, description
28
29| eval dest = query
30
31
32| `security_content_ctime(firstTime)`
33
34| `security_content_ctime(lastTime)`
35
36
37| `remote_access_software_usage_exceptions`
38
39
40| `detect_remote_access_software_usage_dns_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 22	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

Name	Value
security_content_summariesonly	`summariesonly=`summariesonly_config `allow_old_summaries=`oldsummaries_config `fillnull_value=`fillnull_config``
detect_remote_access_software_usage_dns_filter	`search *`

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

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1219	Remote Access Tools	Command and Control

Command and Control

DE.AE

CIS 10

Default Configuration

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

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Finding (Notable)	No
Creates Intermediate Finding (Risk Event)	Yes

Anomaly detections generate Intermediate Findings (Risk Events). They do not generate a Finding (Notable) directly.

Implementation

To implement this search, you must ingest logs that contain the DNS query and the source of the query. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the DNS logs. The logs must also be mapped to the Network_Resolution data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process. The "remote_access_software_usage_exceptions" macro leverages both an Assets and Identities lookup, as well as a KVStore collection called "remote_software_exceptions" that lets you track and maintain device-based exceptions for this set of detections.

Known False Positives

It is possible that legitimate remote access software is used within the environment. Ensure that the lookup is reviewed and updated with any additional remote access software that is used within the environment. Known false positives can be added to the remote_access_software_usage_exception.csv lookup to globally suppress these situations across all remote access content

Associated Analytic Story

Intermediate Findings

Message	Entity Field	Entity Type	Risk Score
A domain [$query$] for a known remote access software [$signature$] was contacted by [$src$].	src	system	20

Threat Objects

Field	Type
signature	signature
query	domain

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`

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: 16