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Description

The analytic is crafted to detect potential download of cryptomining software within a network that is blocked by Zscaler. Utilizing Splunk search functionality, it sifts through web proxy logs for blocked actions associated with cryptominer threats. Key data points like the device owner, user, URL category, destination URL and IP, and action taken are analyzed to highlight possible cryptominer downloads. This detection, categorized as an anomaly, aids in early identification and mitigation of cryptomining activities, ensuring network integrity and resource availability.

  • Type: Anomaly

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2023-10-30
  • Author: Gowthamaraj Rajendran, Rod Soto, Splunk
  • ID: ed76ce37-bab9-4ec0-bf3e-9c6a6cf43365

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1566 Phishing Initial Access
Kill Chain Phase
  • Delivery
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


1
2
3
4
5



`zscaler_proxy` action=blocked threatname=*miner* 
| stats count min(_time) as firstTime max(_time) as lastTime by action deviceowner user urlcategory url src dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `zscaler_cryptominer_downloaded_threat_blocked_filter`

Macros

The SPL above uses the following Macros:

:information_source: zscaler_cryptominer_downloaded_threat_blocked_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.

  • action
  • threatname
  • deviceowner
  • user
  • urlcategory
  • url
  • dest
  • dest_ip
  • action

How To Implement

You must install the latest version of Zscaler Add-on from Splunkbase. You must be ingesting Zscaler events into your Splunk environment through an ingester. This analytic was written to be used with the "zscalernss-web" sourcetype leveraging the Zscaler proxy data. This enables the integration with Splunk Enterprise Security. Security teams are encouraged to adjust the detection parameters, ensuring the detection is tailored to their specific environment.

Known False Positives

False positives are limited to Zscaler configuration.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
32.0 40 80 Potential CryptoMiner Downloaded Threat from dest -[$dest$] on $src$ for user-[$user$].

: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

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