Power Automate - Unusual bulk deletion of flow resources

Status: available
Severity: medium
Time window: 14d
Group by: ActorName, ActorUserId, UserUpn
Source: github.com/Azure/Azure-Sentinel

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.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1562` Impair Defenses
Impact	`T1485` Data Destruction
Impact	`T0828` Loss of Productivity and Revenue

Rule body kusto

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

Stages and Predicates

Parameters

let minThreshold = 10;
let interval = 1h;
let startTime = ago(14d);
let endTime = now();
let query_frequency = 1h;

The stages below define let flow_deletion_events (the rule's main pipeline source).

Stage 1: `source`

PowerAutomateActivity

Stage 2: `where`

| where TimeGenerated >= startTime

Stage 3: `where`

| where EventOriginalType =~ "DeleteFlow"

Stage 4: `extend`

| extend IngestionTimeGenerated = TimeGenerated

The stages below score time-series anomalies (make-series, series_decompose_anomalies).

The stages below run on flow_deletion_events (the outer pipeline).

Stage 5: `summarize`

flow_deletion_events
| make-series DeletedFlowCount=count() on IngestionTimeGenerated from startTime to endTime step interval by ActorName, UserUpn, ActorUserId

Threshold: ge 10

Stage 6: `extend`

| extend(Anomalies, AnomalyScore, ExpectedUsage) = series_decompose_anomalies(DeletedFlowCount)

Stage 7: `mv-expand`

| mv-expand
    DeletedFlowCount to typeof(double),
    IngestionTimeGenerated to typeof(datetime),
    Anomalies to typeof(double),
    AnomalyScore to typeof(double),
    ExpectedUsage to typeof(long)

Stage 8: `where`

| where IngestionTimeGenerated >= ago(query_frequency)

Stage 9: `where`

| where Anomalies != 0 and DeletedFlowCount >= minThreshold

Stage 10: `kusto:lookup`

| lookup (flow_deletion_events
    | where IngestionTimeGenerated >= ago(query_frequency))
    on ActorName, UserUpn, ActorUserId

Stage 11: `extend`

| extend
    AccountName = tostring(split(ActorName, "@")[0]),
    UPNSuffix = tostring(split(ActorName, "@")[1]),
    PowerAutomateAppId = 27592

Stage 12: `project`

| project
    TimeGenerated,
    ActorName,
    DeletedFlowCount,
    ExpectedUsage,
    Anomalies,
    AnomalyScore,
    AccountName,
    UPNSuffix,
    PowerAutomateAppId,
    UserUpn,
    ActorUserId

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.

Field	Kind	Values
`Anomalies`	ne	`0` transforms: `cased`
`DeletedFlowCount`	ge	`10` transforms: `cased`
`EventOriginalType`	eq	`DeleteFlow`
`TimeGenerated`	ge	`startTime` 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.

Field	Source
`AccountName`	`project`
`ActorName`	`project`
`ActorUserId`	`project`
`Anomalies`	`project`
`AnomalyScore`	`project`
`DeletedFlowCount`	`project`
`ExpectedUsage`	`project`
`PowerAutomateAppId`	`project`
`TimeGenerated`	`project`
`UPNSuffix`	`project`
`UserUpn`	`project`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Power Automate - Unusual bulk deletion of flow resources

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `summarize`

Stage 6: `extend`

Stage 7: `mv-expand`

Stage 8: `where`

Stage 9: `where`

Stage 10: `kusto:lookup`

Stage 11: `extend`

Stage 12: `project`

Indicators

Output fields

Keyboard shortcuts

Search operators

Power Automate - Unusual bulk deletion of flow resources

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend

Stage 5: summarize

Stage 6: extend

Stage 7: mv-expand

Stage 8: where

Stage 9: where

Stage 10: kusto:lookup

Stage 11: extend

Stage 12: project

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `summarize`

Stage 6: `extend`

Stage 7: `mv-expand`

Stage 8: `where`

Stage 9: `where`

Stage 10: `kusto:lookup`

Stage 11: `extend`

Stage 12: `project`