The following analytic identifies a dns query to a known TOR proxy website. This technique was seen in several adversaries, threat actors and malware like AgentTesla to To disguise the source of its malicious traffic. adversaries may chain together multiple proxies. This Anomaly detection might be a good pivot for a process trying to download or use TOR proxies in a compromised host machine.
- Type: Anomaly
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2022-09-16
- Author: Teoderick Contreras, Splunk
- ID: 4c2d198b-da58-48d7-ba27-9368732d0054
Kill Chain Phase
- Command and Control
- CIS 10
1 2 3 4 5 6 `sysmon` EventCode=22 QueryName IN ("*.torproject.org", "www.theonionrouter.com") | stats count min(_time) as firstTime max(_time) as lastTime by Image QueryName QueryStatus ProcessId Computer | rename Computer as dest | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_multi_hop_proxy_tor_website_query_filter`
The SPL above uses the following Macros:
windows_multi_hop_proxy_tor_website_query_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
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.
Associated Analytic Story
|25.0||50||50||a process $Image$ is having a dns query in a tor domain $QueryName$ in $dest$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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