Detection rules › Splunk
Windows Multi hop Proxy TOR Website Query
The following analytic identifies DNS queries to known TOR proxy websites, such as "*.torproject.org" and "www.theonionrouter.com". It leverages Sysmon EventCode 22 to detect these queries by monitoring DNS query events from endpoints. This activity is significant because adversaries often use TOR proxies to disguise the source of their malicious traffic, making it harder to trace their actions. If confirmed malicious, this behavior could indicate an attempt to obfuscate network traffic, potentially allowing attackers to exfiltrate data or communicate with command and control servers undetected.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Command & Control | T1071.003 Application Layer Protocol: Mail Protocols |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 22 | DNSEvent (DNS query) |
Rule body splunk
name: Windows Multi hop Proxy TOR Website Query
id: 4c2d198b-da58-48d7-ba27-9368732d0054
version: 12
creation_date: '2022-09-21'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic identifies DNS queries to known TOR proxy websites, such as "*.torproject.org" and "www.theonionrouter.com". It leverages Sysmon EventCode 22 to detect these queries by monitoring DNS query events from endpoints. This activity is significant because adversaries often use TOR proxies to disguise the source of their malicious traffic, making it harder to trace their actions. If confirmed malicious, this behavior could indicate an attempt to obfuscate network traffic, potentially allowing attackers to exfiltrate data or communicate with command and control servers undetected.
data_source:
- Sysmon EventID 22
search: |-
`sysmon` EventCode=22 QueryName IN ("*.torproject.org", "www.theonionrouter.com")
| stats count min(_time) as firstTime max(_time) as lastTime
BY answer answer_count dvc
process_exec process_guid process_name
query query_count reply_code_id
signature signature_id src
user_id vendor_product QueryName
QueryResults QueryStatus
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_multi_hop_proxy_tor_website_query_filter`
how_to_implement: To successfully implement this search, you need to be ingesting logs with the process name and sysmon eventcode = 22 dns query events from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
known_false_positives: third party application may use this proxies if allowed in production environment. Filter is needed.
references:
- https://malpedia.caad.fkie.fraunhofer.de/details/win.agent_tesla
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"
intermediate_findings:
entities:
- field: dvc
type: system
score: 20
message: a process $process_name$ is having a dns query in a tor domain $QueryName$ in $dvc$
analytic_story:
- AgentTesla
- Interlock Ransomware
asset_type: Endpoint
mitre_attack_id:
- T1071.003
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: network
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/agent_tesla/agent_tesla_tor_dns_query/sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: XmlWinEventLog
test_type: unit
Stages and Predicates
Stage 1: search
`sysmon` EventCode=22 QueryName IN ("*.torproject.org", "www.theonionrouter.com")
Stage 2: stats
| stats count min(_time) as firstTime max(_time) as lastTime
BY answer answer_count dvc
process_exec process_guid process_name
query query_count reply_code_id
signature signature_id src
user_id vendor_product QueryName
QueryResults QueryStatus
Stage 3: search
| `security_content_ctime(firstTime)`
Stage 4: search
| `security_content_ctime(lastTime)`
Stage 5: search
| `windows_multi_hop_proxy_tor_website_query_filter`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.