Detection: Windows Multi hop Proxy TOR Website Query

Updated Date: 2024-05-22 ID: 4c2d198b-da58-48d7-ba27-9368732d0054 Author: Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

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.

1`sysmon` EventCode=22 QueryName IN ("*.torproject.org", "www.theonionrouter.com") 
2| stats count min(_time) as firstTime max(_time) as lastTime by Image QueryName QueryStatus ProcessId  Computer 
3| rename Computer as dest 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_multi_hop_proxy_tor_website_query_filter`

Data Source

Name Platform Sourcetype Source Supported App
Sysmon EventID 22 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
windows_multi_hop_proxy_tor_website_query_filter search *
windows_multi_hop_proxy_tor_website_query_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1071.003 Mail Protocols Command And Control
T1071 Application Layer Protocol Command And Control
KillChainPhase.COMMAND_AND_CONTROL
NistCategory.DE_AE
Cis18Value.CIS_10
APT28
APT32
Kimsuky
SilverTerrier
Turla
Magic Hound
Rocke
TeamTNT

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

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.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
a process $Image$ is having a dns query in a tor domain $QueryName$ in $dest$ 25 50 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational xmlwineventlog
Integration ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational xmlwineventlog

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: GitHub | Version: 2