Power Automate - Unusual bulk deletion of flow resources

id: 56cb646e-56a0-4f0e-8866-9bc1dd15da78
kind: Scheduled
name: Power Automate - Unusual bulk deletion of flow resources
description: Identifies bulk deletion of Power Automate flows that exceed a predefined
  threshold defined in the query and deviate from activity patterns observed in the
  last 14 days.
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: PowerAutomate
    dataTypes:
      - PowerAutomateActivity
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Impact
  - DefenseEvasion
relevantTechniques:
  - T1485
  - T0828
  - T1562
query: |
  // minThreshold: Minimum number of apps to be deleted to be considered an anomaly;
  // This is to prevent one-off isolated delete flow to be considered outlier.
  // The Min Threshold can be reduced or increased according to the traffic in the organization.
  let minThreshold=10;
  let interval = 1h;
  let startTime = ago(14d);
  let endTime = now();
  let query_frequency = 1h;
  let flow_deletion_events = PowerAutomateActivity
      | where TimeGenerated >= startTime
      | where EventOriginalType =~ "DeleteFlow"
      | extend IngestionTimeGenerated = TimeGenerated;
  flow_deletion_events
  | make-series DeletedFlowCount=count() on IngestionTimeGenerated from startTime to endTime step interval by ActorName, UserUpn, ActorUserId
  | extend(Anomalies, AnomalyScore, ExpectedUsage) = series_decompose_anomalies(DeletedFlowCount)
  | mv-expand
      DeletedFlowCount to typeof(double),
      IngestionTimeGenerated to typeof(datetime),
      Anomalies to typeof(double),
      AnomalyScore to typeof(double),
      ExpectedUsage to typeof(long)
  | where IngestionTimeGenerated >= ago(query_frequency)
  | where Anomalies != 0 and DeletedFlowCount >= minThreshold
  | lookup (flow_deletion_events
      | where IngestionTimeGenerated >= ago(query_frequency))
      on ActorName, UserUpn, ActorUserId
  | extend
      AccountName = tostring(split(ActorName, "@")[0]),
      UPNSuffix = tostring(split(ActorName, "@")[1]),
      PowerAutomateAppId = 27592
  | project
      TimeGenerated,
      ActorName,
      DeletedFlowCount,
      ExpectedUsage,
      Anomalies,
      AnomalyScore,
      AccountName,
      UPNSuffix,
      PowerAutomateAppId,
      UserUpn,
      ActorUserId
eventGroupingSettings:
  aggregationKind: SingleAlert
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: CloudApplication
    fieldMappings:
      - identifier: AppId
        columnName: PowerAutomateAppId
alertDetailsOverride:
  alertDisplayNameFormat: Power Automate - unusual bulk deletion of {{DeletedFlowCount}}
    flows
  alertDescriptionFormat: User {{ActorName}}  deleted {{DeletedFlowCount}} flows in
    the last hour, surpassing the bulk delete threshold. This is anomalous compared
    to the past 14 days.
customDetails:
  DeletedFlowCount: DeletedFlowCount
version: 3.2.0