detection.wiki

Detection rules › Kusto

Cisco WSA - Access to unwanted site

Status
available
Severity
high
Time window
1h
Source
github.com/Azure/Azure-Sentinel

'Detects when users attempting to access sites from high risk category.'

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1566 Phishing

Rule body kusto

id: 38029e86-030c-46c4-8a91-a2be7c74d74c
name: Cisco WSA - Access to unwanted site
description: |
  'Detects when users attempting to access sites from high risk category.'
severity: High
status: Available
requiredDataConnectors:
  - connectorId: SyslogAma
    datatypes:
      - Syslog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1566
query: |
  let risky_sites = dynamic(['IW_adlt', 'IW_hack', 'IW_porn']);
  CiscoWSAEvent
  | where UrlCategory in~ (risky_sites)
  | where DvcAction =~ 'DEFAULT_CASE'
  | extend AccountCustomEntity = SrcUserName
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountCustomEntity
version: 1.0.3
kind: Scheduled

Stages and Predicates

Parameters

let risky_sites = dynamic(['IW_adlt', 'IW_hack', 'IW_porn']);

Stage 1: source

CiscoWSAEvent

Stage 2: where

| where UrlCategory in~ (risky_sites)

Stage 3: where

| where DvcAction =~ 'DEFAULT_CASE'

Stage 4: extend

| extend AccountCustomEntity = SrcUserName

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
DvcActioneq
  • DEFAULT_CASE
UrlCategoryin
  • IW_adlt
  • IW_hack
  • IW_porn

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
AccountCustomEntityextend