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Detection rules › Kusto

Semperis DSP Well-known privileged SIDs in sIDHistory

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

'This indicator looks for security principals that contain specific SIDs of accounts from built-in privileged groups within their sIDHistory attribute. This would allow those security principals to have the same privileges as those privileged accounts, but in a way that is not obvious to monitor (e.g. through group membership).'

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1134 Access Token Manipulation
StealthT1134 Access Token Manipulation

Rule body kusto

id: ddd75d93-5b8b-4349-babe-c4e15343c5a3
name: Semperis DSP Well-known privileged SIDs in sIDHistory
description: |
  'This indicator looks for security principals that contain specific SIDs of accounts from built-in privileged groups within their sIDHistory attribute. This would allow those security principals to have the same privileges as those privileged accounts, but in a way that is not obvious to monitor (e.g. through group membership).'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: SemperisDSP
    dataTypes:
      - dsp_parser
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - PrivilegeEscalation
  - DefenseEvasion
relevantTechniques:
  - T1134
query: |
  dsp_parser
  | where EventID == 9212
  | where SecurityIndicatorName == "Well-known privileged SIDs in sIDHistory"
  | extend HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: DnsDomain
version: 2.0.7
kind: Scheduled

Stages and Predicates

Stage 1: source

dsp_parser

Stage 2: where

| where EventID == 9212

Stage 3: where

| where SecurityIndicatorName == "Well-known privileged SIDs in sIDHistory"

Stage 4: extend

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

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
EventIDeq
  • 9212 transforms: cased
SecurityIndicatorNameeq
  • Well-known privileged SIDs in sIDHistory 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
DnsDomainextend
HostNameextend