Remcos RAT File Creation in Remcos Folder

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Description

This search is to detect file creation in remcos folder in appdata which is the keylog and clipboard logs that will be send to its c2 server. This is really a good TTP indicator that there is a remcos rat in the system that do keylogging, clipboard grabbing and audio recording.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-09-21
• Author: Teoderick Contreras, Splunk, Sanjay Govind
• ID: 25ae862a-1ac3-11ec-94a1-acde48001122

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1113	Screen Capture	Collection

Kill Chain Phase

• Exploitation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

|tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem where Filesystem.file_name IN ("*.dat") Filesystem.file_path = "*\\remcos\\*" by _time Filesystem.file_name Filesystem.file_path Filesystem.dest Filesystem.file_create_time 
| `drop_dm_object_name(Filesystem)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `remcos_rat_file_creation_in_remcos_folder_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• security_content_summariesonly

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

Required fields

List of fields required to use this analytic.

• _time
• dest
• file_create_time
• file_name
• file_path

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known False Positives

unknown

Associated Analytic Story

• Remcos

RBA

Risk Score	Impact	Confidence	Message
100.0	100	100	file $file_name$ created in $file_path$ of $dest$

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

• https://success.trendmicro.com/dcx/s/solution/1123281-remcos-malware-information?language=en_US
• https://blog.malwarebytes.com/threat-intelligence/2021/07/remcos-rat-delivered-via-visual-basic/

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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