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Detection rules › Kusto

ApexOne - Suspicious connections

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

'Detects suspicious connections.'

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1102 Web Service

Rule body kusto

id: 9e3dc038-67b7-11ec-90d6-0242ac120003
name: ApexOne - Suspicious connections
description: |
  'Detects suspicious connections.'
severity: High
status: Available
requiredDataConnectors:
  - connectorId: CefAma
    dataTypes:
      - CommonSecurityLog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1102
query: |
  TMApexOneEvent
  | where EventMessage has "Suspicious Connection"
  | where NetworkDirection == 1 
  | where DvcAction in ('1', '3')
  | extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = DstUserName
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPCustomEntity
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountCustomEntity
version: 1.0.3
kind: Scheduled

Stages and Predicates

Stage 1: source

TMApexOneEvent

Stage 2: where

| where EventMessage has "Suspicious Connection"

Stage 3: where

| where NetworkDirection == 1

Stage 4: where

| where DvcAction in ('1', '3')

Stage 5: extend

| extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = DstUserName

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
DvcActionin
  • 1 transforms: cased
  • 3 transforms: cased
EventMessagematch
  • Suspicious Connection transforms: term
NetworkDirectioneq
  • 1 transforms: cased

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
IPCustomEntityextend