Windows Modify Registry ValleyRAT C2 Config

SPLUNK detection rule by Teoderick Contreras, Splunk · Apache-2.0

The following analytic detects modifications to theregistry related to ValleyRAT C2 configuration. Specifically, it monitors changes in registry keys where ValleyRAT saves the IP address and port information of its command-and-control (C2) server. This activity is a key indicator of ValleyRAT attempting to establish persistent communication with its C2 infrastructure. By identifying these unauthorized registry modifications, security analysts can quickly detect malicious configurations and investigate the associated threats. Early detection of these changes helps prevent further exploitation and limits the malware’s ability to exfiltrate data or control infected systems.

name: Windows Modify Registry ValleyRAT C2 Config
id: ac59298a-8d81-4c02-8c9b-ffdac993891f
version: 12
creation_date: '2024-09-18'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: "The following analytic detects modifications to theregistry related to ValleyRAT C2 configuration. Specifically,  it monitors changes in registry keys where ValleyRAT saves the IP address and port information of its command-and-control (C2) server. This activity is a key indicator of ValleyRAT attempting to establish persistent communication with its C2 infrastructure. By identifying these unauthorized registry modifications, security analysts can quickly detect malicious configurations and investigate the associated threats. Early detection of these changes helps prevent further exploitation and limits the malware’s ability to exfiltrate data or control infected systems."
data_source:
    - Sysmon EventID 13
search: '| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path= "*\\Console\\IpDateInfo" AND Registry.registry_value_data="Binary Data") OR (Registry.registry_path= "*\\Console\\SelfPath" AND Registry.registry_value_data="*.exe") by Registry.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product | `drop_dm_object_name(Registry)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_modify_registry_valleyrat_c2_config_filter`'
how_to_implement: To successfully implement this search, you need to be ingesting logs with the registry value name, registry path, and registry value data from your endpoints. If you are using Sysmon, you must have at least version 2.0 of the official Sysmon TA. https://splunkbase.splunk.com/app/5709
known_false_positives: No false positives have been identified at this time.
references:
    - https://www.proofpoint.com/us/blog/threat-insight/chinese-malware-appears-earnest-across-cybercrime-threat-landscape
    - https://www.fortinet.com/blog/threat-research/valleyrat-campaign-targeting-chinese-speakers
drilldown_searches:
    - name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | 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: A registry modification related to ValleyRAT on [$dest$]
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: A registry modification related to ValleyRAT on [$dest$]
analytic_story:
    - ValleyRAT
asset_type: Endpoint
mitre_attack_id:
    - T1112
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/attack_techniques/T1112/valleyrat_c2_reg2/valleyrat_c2_reg2.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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