Detection rules › Kusto

Tenable.ad DCSync

Severity
high
Time window
2h
Source
github.com/Azure/Azure-Sentinel

'Searches for DCSync attacks.'

MITRE ATT&CK coverage

TacticTechniques
Credential Access

Rule body

id: 0c8d4de3-adb9-4161-a863-aa1e2c8bd959
name: Tenable.ad DCSync
description: |
    'Searches for DCSync attacks.'
severity: High
requiredDataConnectors:
  - connectorId: Tenable.ad
    dataTypes:
      - Tenable_ad_CL
queryFrequency: 2h
queryPeriod: 2h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CredentialAccess
relevantTechniques:
  - T1003.006
query: |
  // For the query to work properly, make sure you have imported the afad_parser.kql parser into the workspace
  // Retrieve the parser here: https://raw.githubusercontent.com/tenable/Azure-Sentinel/Tenable.ad-connector/Solutions/TenableAD/Parsers/afad_parser.kql
  // Then, create the Kusto Function with alias afad_parser
  afad_parser
    | where MessageType == 2 and Codename == "DCSync"
    | extend HostName = tostring(split(Host, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Host, '.'), 1, -1), '.'))
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: DnsDomain
version: 1.0.1
kind: Scheduled

Stages and Predicates

Stage 1: source

afad_parser

Stage 2: where

| where MessageType == 2 and Codename == "DCSync"

Stage 3: extend

| extend HostName = tostring(split(Host, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Host, '.'), 1, -1), '.'))

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Codenameeq
  • DCSync corpus 3 (kusto 3)
field:"Codename" kind:eq value:"DCSync"
MessageTypeeq
  • 2 corpus 21 (kusto 21)
field:"MessageType" kind:eq value:"2"

Output fields

These fields are emitted when the rule matches.

FieldSource
DnsDomainextend
HostNameextend