Zscaler Adware Activities Threat Blocked

name: Zscaler Adware Activities Threat Blocked
id: 3407b250-345a-4d71-80db-c91e555a3ece
version: 10
creation_date: '2024-04-17'
modification_date: '2026-05-13'
author: Gowthamaraj Rajendran, Splunk
status: production
type: Anomaly
description: The following analytic identifies potential adware activity blocked by Zscaler. It leverages web proxy logs to detect blocked actions associated with adware threats. Key data points such as device owner, user, URL category, destination URL, and IP are analyzed. This activity is significant as adware can degrade system performance, lead to unwanted advertisements, and potentially expose users to further malicious content. If confirmed malicious, it could indicate an attempt to compromise user systems, necessitating further investigation and remediation to prevent potential data breaches or system exploitation.
data_source: []
search: |-
    `zscaler_proxy` action=blocked threatname=*adware*
      | 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_adware_activities_threat_blocked_filter`
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.
references:
    - https://help.zscaler.com/zia/nss-feed-output-format-web-logs
intermediate_findings:
    entities:
        - field: src
          type: system
          score: 20
          message: Potential Adware Activity blocked from dest -[$dest$] on $src$ for user-[$user$].
        - field: user
          type: user
          score: 20
          message: Potential Adware Activity blocked from dest -[$dest$] on $src$ for user-[$user$].
threat_objects:
    - field: url
      type: url
analytic_story:
    - Zscaler Browser Proxy Threats
asset_type: Web Server
mitre_attack_id:
    - T1566
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: web
security_domain: threat