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Description

The following analytic detects the presence of a registry key related to the Remcos RAT agent on a host. This detection is made by a Splunk query to search for instances where the registry key "license" is found in the "Software\Remcos" path. This analytic combines information from two data models: Endpoint.Processes and Endpoint.Registry and retrieves process information such as user, process ID, process name, process path, destination, parent process name, parent process, and process GUID. This analytic also retrieves registry information such as registry path, registry key name, registry value name, registry value data, and process GUID. By joining the process GUID from the Endpoint.Processes data model with the process GUID from the Endpoint.Registry data model, the analytic identifies instances where the "license" registry key is found in the "Software\Remcos" path. This detection is important because it suggests that the host has been compromised by the Remcos RAT agent. Remcos is a well-known remote access Trojan that can be used by attackers to gain unauthorized access to systems and exfiltrate sensitive data. Identifying this behavior allows the SOC to take immediate action to remove the RAT agent and prevent further compromise. The impact of this attack can be severe, as the attacker can gain unauthorized access to the system, steal sensitive information, or use the compromised system as a launching point for further attacks. Next steps include using this analytic in conjunction with other security measures and threat intelligence to ensure accurate detection and response.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2022-11-14
  • Author: Steven Dick, Bhavin Patel, Rod Soto, Teoderick Contreras, Splunk
  • ID: f2a1615a-1d63-11ec-97d2-acde48001122

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1112 Modify Registry Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE
1
2
3
4
5
6
7
8
9
10
11
| tstats `security_content_summariesonly` count min(_time) AS firstTime max(_time) AS lastTime FROM datamodel=Endpoint.Processes BY _time span=1h Processes.user Processes.process_id Processes.process_name Processes.process Processes.process_path Processes.dest Processes.parent_process_name Processes.parent_process Processes.process_guid 
| `drop_dm_object_name(Processes)` 
| join process_guid [ 
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE (Registry.registry_key_name=*\\Software\\Remcos*) BY _time span=1h Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid 
| `drop_dm_object_name(Registry)`] 
| fields firstTime lastTime dest user parent_process_name parent_process process_name process_path process registry_key_name registry_path registry_value_name registry_value_data process_guid 
| where isnotnull(registry_value_data) 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
|`remcos_client_registry_install_entry_filter`

Macros

The SPL above uses the following Macros:

:information_source: remcos_client_registry_install_entry_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
  • Processes.user
  • Processes.dest
  • Processes.process_id
  • Processes.process_name
  • Processes.process
  • Processes.process_path
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.process_guid
  • Registry.dest
  • Registry.registry_value_name
  • Registry.registry_key_name
  • Registry.registry_path
  • Registry.registry_value_data
  • Registry.process_guid

How To Implement

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

unknown

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
90.0 90 100 A registry entry $registry_path$ with registry keyname $registry_key_name$ related to Remcos RAT in host $dest$

:information_source: 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

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