Try in Splunk Security Cloud

Description

The following analytic looks for allowed network traffic to The Onion Router(TOR), a benign anonymity network which can be abused for a variety of nefarious purposes. Detecting Tor traffic is paramount for upholding network security and mitigating potential threats. Tor's capacity to provide users with anonymity has been exploited by cybercriminals for activities like hacking, data breaches, and illicit content dissemination. Additionally, organizations must monitor Tor usage within their networks to ensure compliance with policies and regulations, as it can bypass conventional monitoring and filtering measures. Lastly, the ability to identify Tor traffic empowers security teams to promptly investigate and address potential security incidents, fortifying the protection of sensitive data and preserving the integrity of the network environment.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Network_Traffic
  • Last Updated: 2023-09-20
  • Author: David Dorsey, Bhavin Patel, Splunk
  • ID: ea688274-9c06-4473-b951-e4cb7a5d7a45

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1090 Proxy Command And Control
T1090.003 Multi-hop Proxy Command And Control
Kill Chain Phase
  • Command and Control
NIST
  • DE.CM
CIS20
  • CIS 13
CVE
1
2
3
4
5
6
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Network_Traffic where All_Traffic.app=tor AND All_Traffic.action=allowed by All_Traffic.src_ip All_Traffic.dest_ip All_Traffic.dest_port All_Traffic.action 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `drop_dm_object_name("All_Traffic")` 
| `tor_traffic_filter`

Macros

The SPL above uses the following Macros:

:information_source: tor_traffic_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • All_Traffic.app
  • All_Traffic.action
  • All_Traffic.src_ip
  • All_Traffic.dest_ip
  • All_Traffic.dest_port

How To Implement

In order to properly run this search, Splunk needs to ingest data from Next Generation Firewalls like Palo Alto Networks Firewalls or other network control devices that mediate the traffic allowed into an environment. This is necessary so that the search can identify an 'action' taken on the traffic of interest. The search requires the Network_Traffic data model to be populated.

Known False Positives

None at this time

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
80.0 100 80 Suspicious network traffic allowed using TOR has been detected from $src_ip$ to $dest_ip$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

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 | version: 3