Detection rules › Kusto

Dataverse - Bulk record ownership re-assignment or sharing

Status
available
Severity
medium
Time window
1d
Group by
ClientIp, InstanceUrl, Message, UserId
Source
github.com/Azure/Azure-Sentinel

Identifies individual record ownership changes including sharing of records with other users/teams or re-assignment of ownership exceeding a pre-defined threshold.

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1548 Abuse Elevation Control Mechanism

Rule body kusto

id: 6e480329-84bc-409a-b97b-22e8102af3ca
kind: Scheduled
name: Dataverse - Bulk record ownership re-assignment or sharing
description: Identifies individual record ownership changes including sharing of records
  with other users/teams or re-assignment of ownership exceeding a pre-defined threshold.
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: Dataverse
    dataTypes:
      - DataverseActivity
queryFrequency: 1h
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - PrivilegeEscalation
relevantTechniques:
  - T1548
query: |
  // Set threshold for number of shared/assigned records
  let detection_threshold = 100;
  let query_frequency = 1h;
  DataverseActivity
  | where TimeGenerated >= ago(query_frequency)
  | where Message in ("ModifyAccess", "Assign", "GrantAccess")
  | summarize
      FirstEvent = min(TimeGenerated),
      LastEvent = max(TimeGenerated),
      Events = count()
      by UserId, Message, InstanceUrl, ClientIp
  | where Events > detection_threshold
  | extend
      CloudAppId = int(32780),
      AccountName = tostring(split(UserId, '@')[0]),
      UPNSuffix = tostring(split(UserId, '@')[1])
  | project
      FirstEvent,
      LastEvent,
      Message,
      Events,
      UserId,
      ClientIp,
      InstanceUrl,
      CloudAppId,
      AccountName,
      UPNSuffix
eventGroupingSettings:
  aggregationKind: AlertPerResult
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: ClientIp
  - entityType: CloudApplication
    fieldMappings:
      - identifier: AppId
        columnName: CloudAppId
      - identifier: InstanceName
        columnName: InstanceUrl
alertDetailsOverride:
  alertDisplayNameFormat: Dataverse - High number of record access modification events
    detected
  alertDescriptionFormat: '{{Events}} events of type {{Message}} detected in {{InstanceUrl}}
    could indicate suspicious or malicious activity.'
version: 3.2.0

Stages and Predicates

Parameters

let detection_threshold = 100;
let query_frequency = 1h;

Stage 1: source

DataverseActivity

Stage 2: where

| where TimeGenerated >= ago(query_frequency)

Stage 3: where

| where Message in ("ModifyAccess", "Assign", "GrantAccess")

Stage 4: summarize

| summarize
    FirstEvent = min(TimeGenerated),
    LastEvent = max(TimeGenerated),
    Events = count()
    by UserId, Message, InstanceUrl, ClientIp
Threshold
gt 100

Stage 5: where

| where Events > detection_threshold

Stage 6: extend

| extend
    CloudAppId = int(32780),
    AccountName = tostring(split(UserId, '@')[0]),
    UPNSuffix = tostring(split(UserId, '@')[1])

Stage 7: project

| project
    FirstEvent,
    LastEvent,
    Message,
    Events,
    UserId,
    ClientIp,
    InstanceUrl,
    CloudAppId,
    AccountName,
    UPNSuffix

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
Eventsgt
  • 100 transforms: cased
Messagein
  • Assign transforms: cased
  • GrantAccess transforms: cased
  • ModifyAccess 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
AccountNameproject
ClientIpproject
CloudAppIdproject
Eventsproject
FirstEventproject
InstanceUrlproject
LastEventproject
Messageproject
UPNSuffixproject
UserIdproject