Detection rules › Splunk

Zscaler Employment Search Web Activity

Status
production
Severity
low
Group by
action, dest, deviceowner, src, url, urlcategory, user
Author
Gowthamaraj Rajendran, Rod Soto, Splunk
Source
github.com/splunk/security_content

The following analytic identifies web activity related to employment searches within a network. It leverages Zscaler web proxy logs, focusing on entries categorized as 'Job/Employment Search'. Key data points such as device owner, user, URL category, destination URL, and IP are analyzed. This detection is significant for SOCs as it helps monitor potential insider threats by identifying users who may be seeking new employment. If confirmed malicious, this activity could indicate a risk of data exfiltration or other insider threats, potentially leading to sensitive information leakage or other security breaches.

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1566 Phishing

Rule body splunk

name: Zscaler Employment Search Web Activity
id: 5456bdef-d765-4565-8e1f-61ca027bc50e
version: 9
creation_date: '2024-04-17'
modification_date: '2026-05-13'
author: Gowthamaraj Rajendran, Rod Soto, Splunk
status: production
type: Anomaly
description: The following analytic identifies web activity related to employment searches within a network. It leverages Zscaler web proxy logs, focusing on entries categorized as 'Job/Employment Search'. Key data points such as device owner, user, URL category, destination URL, and IP are analyzed. This detection is significant for SOCs as it helps monitor potential insider threats by identifying users who may be seeking new employment. If confirmed malicious, this activity could indicate a risk of data exfiltration or other insider threats, potentially leading to sensitive information leakage or other security breaches.
data_source: []
search: |-
    `zscaler_proxy` urlsupercategory="Job/Employment Search"
      | 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_employment_search_web_activity_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
drilldown_searches:
    - name: View the detection results for - "$src$" and "$user$"
      search: '%original_detection_search% | search  src = "$src$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$src$" and "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$src$", "$user$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
intermediate_findings:
    entities:
        - field: src
          type: system
          score: 20
          message: Potential Employment Search Web Activity from dest -[$dest$] on $src$ for user-[$user$].
        - field: user
          type: user
          score: 20
          message: Potential Employment Search Web Activity 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
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566/zscalar_web_proxy/zscalar_web_proxy.json
          source: zscaler
          sourcetype: zscalernss-web
      test_type: unit

Stages and Predicates

Stage 1: search

`zscaler_proxy` urlsupercategory="Job/Employment Search"

Stage 2: stats

| stats count min(_time) as firstTime max(_time) as lastTime
    BY action deviceowner user
       urlcategory url src
       dest

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `zscaler_employment_search_web_activity_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
sourcetypeeq
  • zscalernss-web
urlsupercategoryeq
  • "Job/Employment Search"