Detection rules › Splunk
Zscaler Legal Liability Threat Blocked
The following analytic identifies significant legal liability threats blocked by the Zscaler web proxy. It uses web proxy logs to track destinations, device owners, users, URL categories, and actions associated with legal liability. By leveraging statistics on unique fields, it ensures a precise focus on these threats. This activity is significant for SOC as it helps enforce legal compliance and risk management. If confirmed malicious, it could indicate attempts to access legally sensitive or restricted content, potentially leading to legal repercussions and compliance violations.
Known false positives
- False positives are limited to Zscaler configuration.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access |
Rule body
name: Zscaler Legal Liability Threat Blocked
id: bbf55ebf-c416-4f62-94d9-4064f2a28014
version: 9
creation_date: '2024-04-17'
modification_date: '2026-05-13'
author: Rod Soto, Gowthamaraj Rajendran, Splunk
status: production
type: Anomaly
description: The following analytic identifies significant legal liability threats blocked by the Zscaler web proxy. It uses web proxy logs to track destinations, device owners, users, URL categories, and actions associated with legal liability. By leveraging statistics on unique fields, it ensures a precise focus on these threats. This activity is significant for SOC as it helps enforce legal compliance and risk management. If confirmed malicious, it could indicate attempts to access legally sensitive or restricted content, potentially leading to legal repercussions and compliance violations.
data_source: []
search: |-
`zscaler_proxy` urlclass="Legal Liability"
| 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)`
| dedup urlcategory
| `zscaler_legal_liability_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 Legal Liability Threat from dest -[$dest$] on $src$ for user-[$user$].
- field: user
type: user
score: 20
message: Potential Legal Liability Threat 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
Stages and Predicates
Stage 1: search
`zscaler_proxy` urlclass="Legal Liability"
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: dedup
| dedup urlcategory
Stage 6: search
| `zscaler_legal_liability_threat_blocked_filter`
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
sourcetype | eq |
| field:"sourcetype" kind:eq value:"zscalernss-web" |
urlclass | eq |
| field:"urlclass" kind:eq |