Remcos RAT File Creation in Remcos Folder

name: Remcos RAT File Creation in Remcos Folder
id: 25ae862a-1ac3-11ec-94a1-acde48001122
version: 11
creation_date: '2021-09-22'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk, Sanjay Govind
status: production
type: TTP
description: The following analytic detects the creation of files in the Remcos folder within the AppData directory, specifically targeting keylog and clipboard log files. It leverages the Endpoint.Filesystem data model to identify .dat files created in paths containing "remcos." This activity is significant as it indicates the presence of the Remcos RAT, which performs keylogging, clipboard capturing, and audio recording. If confirmed malicious, this could lead to unauthorized data exfiltration and extensive surveillance capabilities for the attacker.
data_source:
    - Sysmon EventID 11
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 Filesystem.action Filesystem.dest Filesystem.file_access_time Filesystem.file_create_time Filesystem.file_hash Filesystem.file_modify_time Filesystem.file_name Filesystem.file_path Filesystem.file_acl Filesystem.file_size Filesystem.process_guid Filesystem.process_id Filesystem.user Filesystem.vendor_product | `drop_dm_object_name(Filesystem)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `remcos_rat_file_creation_in_remcos_folder_filter`'
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: No false positives have been identified at this time.
references:
    - 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/
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: file $file_name$ created in $file_path$ of $dest$
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Remcos
asset_type: Endpoint
mitre_attack_id:
    - T1113
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/remcos/remcos_agent/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit