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| 1 | +name: Windows TOR Client Execution |
| 2 | +id: f164bc6f-ecbe-45e0-aaa6-f5c4d8c84b9a |
| 3 | +version: 1 |
| 4 | +date: '2026-02-02' |
| 5 | +author: Vignesh Subramanian, Splunk |
| 6 | +status: production |
| 7 | +type: Anomaly |
| 8 | +description: | |
| 9 | + The following analytic detects the execution of the TOR Browser and related TOR components on Windows endpoints by monitoring process creation activity. |
| 10 | + Adversaries and insider threats leverage TOR to anonymize command-and-control traffic, facilitate data exfiltration, and evade network monitoring and policy enforcement. |
| 11 | + While TOR can be used for legitimate research and privacy purposes, its presence on enterprise endpoints is often unusual and should be investigated to determine intent, scope, and any associated malicious behavior. |
| 12 | +data_source: |
| 13 | + - CrowdStrike ProcessRollup2 |
| 14 | + - Sysmon EventID 1 |
| 15 | + - Windows Event Log Security 4688 |
| 16 | +search: | |
| 17 | + | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime |
| 18 | + from datamodel=Endpoint.Processes where |
| 19 | + ( |
| 20 | + Processes.process_name = "tor.exe" |
| 21 | + OR |
| 22 | + ( |
| 23 | + Processes.process_path = "*\\BraveSoftware\\Brave-Browser*" |
| 24 | + Processes.process_path = "*\\tor-*" |
| 25 | + ) |
| 26 | + ) |
| 27 | + by Processes.action Processes.dest Processes.original_file_name |
| 28 | + Processes.parent_process Processes.parent_process_exec |
| 29 | + Processes.parent_process_guid Processes.parent_process_id |
| 30 | + Processes.parent_process_name Processes.parent_process_path |
| 31 | + Processes.process Processes.process_exec Processes.process_guid |
| 32 | + Processes.process_hash Processes.process_id Processes.process_integrity_level |
| 33 | + Processes.process_name Processes.process_path Processes.user |
| 34 | + Processes.user_id Processes.vendor_product |
| 35 | + | `drop_dm_object_name(Processes)` |
| 36 | + | `security_content_ctime(firstTime)` |
| 37 | + | `security_content_ctime(lastTime)` |
| 38 | + | `windows_tor_client_execution_filter` |
| 39 | +how_to_implement: | |
| 40 | + The detection is based on data that originates from Endpoint Detection |
| 41 | + and Response (EDR) agents. These agents are designed to provide security-related |
| 42 | + telemetry from the endpoints where the agent is installed. To implement this search, |
| 43 | + you must ingest logs that contain the process GUID, process name, and parent process. |
| 44 | + Additionally, you must ingest complete command-line executions. These logs must |
| 45 | + be processed using the appropriate Splunk Technology Add-ons that are specific to |
| 46 | + the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` |
| 47 | + data model. Use the Splunk Common Information Model (CIM) to normalize the field |
| 48 | + names and speed up the data modeling process. |
| 49 | +known_false_positives: | |
| 50 | + This detection focuses on TOR-related processes and may generate benign matches in environments where TOR is intentionally used, such as security testing, research, or lab environments. |
| 51 | +references: |
| 52 | + - https://unit42.paloaltonetworks.com/tor-traffic-enterprise-networks/ |
| 53 | + - https://attack.mitre.org/software/S0183/ |
| 54 | + - https://attack.mitre.org/techniques/T1090/003/ |
| 55 | +drilldown_searches: |
| 56 | + - name: View the detection results for - "$user$" and "$dest$" |
| 57 | + search: '%original_detection_search% | search user = "$user$" dest = "$dest$"' |
| 58 | + earliest_offset: $info_min_time$ |
| 59 | + latest_offset: $info_max_time$ |
| 60 | + - name: View risk events for the last 7 days for - "$user$" and "$dest$" |
| 61 | + search: |
| 62 | + '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", |
| 63 | + "$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time) |
| 64 | + as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk |
| 65 | + Message" values(analyticstories) as "Analytic Stories" values(annotations._all) |
| 66 | + as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" |
| 67 | + by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' |
| 68 | + earliest_offset: $info_min_time$ |
| 69 | + latest_offset: $info_max_time$ |
| 70 | +rba: |
| 71 | + message: TOR client process $process_name$ was launched by parent process $parent_process_name$ on host $dest$ by the user $user$ with command line $process$ |
| 72 | + risk_objects: |
| 73 | + - field: dest |
| 74 | + type: system |
| 75 | + score: 40 |
| 76 | + - field: user |
| 77 | + type: user |
| 78 | + score: 40 |
| 79 | + threat_objects: |
| 80 | + - field: parent_process_name |
| 81 | + type: parent_process_name |
| 82 | + - field: process_name |
| 83 | + type: process_name |
| 84 | + - field: process |
| 85 | + type: process |
| 86 | +tags: |
| 87 | + analytic_story: |
| 88 | + - Compromised Windows Host |
| 89 | + - Windows Post-Exploitation |
| 90 | + - Command And Control |
| 91 | + - Data Exfiltration |
| 92 | + - Data Protection |
| 93 | + asset_type: Endpoint |
| 94 | + mitre_attack_id: |
| 95 | + - T1090.003 |
| 96 | + product: |
| 97 | + - Splunk Enterprise |
| 98 | + - Splunk Enterprise Security |
| 99 | + - Splunk Cloud |
| 100 | + security_domain: endpoint |
| 101 | +tests: |
| 102 | + - name: True Positive Test |
| 103 | + attack_data: |
| 104 | + - data: https://media.githubusercontent.com/media/splunk/attack_data/refs/heads/master/datasets/attack_techniques/T1090.003/windows_tor_client_execution/windows-sysmon.log |
| 105 | + sourcetype: XmlWinEventLog |
| 106 | + source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
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