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Detection rules › Kusto

Digital Guardian - Exfiltration using DNS protocol

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

'Detects exfiltration using DNS protocol.'

MITRE ATT&CK coverage

TacticTechniques
ExfiltrationT1048 Exfiltration Over Alternative Protocol

Rule body kusto

id: 39e25deb-49bb-4cdb-89c1-c466d596e2bd
name: Digital Guardian - Exfiltration using DNS protocol
description: |
  'Detects exfiltration using DNS protocol.'
severity: High
status: Available
requiredDataConnectors:
  - connectorId: SyslogAma
    datatypes:
      - Syslog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Exfiltration
relevantTechniques:
  - T1048
query: |
  DigitalGuardianDLPEvent
  | where DstPortNumber == 53
  | extend AccountCustomEntity = SrcUserName
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountCustomEntity
version: 1.0.2
kind: Scheduled

Stages and Predicates

Stage 1: source

DigitalGuardianDLPEvent

Stage 2: where

| where DstPortNumber == 53

Stage 3: 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
DstPortNumbereq
  • 53 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