Mass Cloud resource deletions Time Series Anomaly

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Id	ed43bdb7-eaab-4ea4-be52-6951fcfa7e3b
Rulename	Mass Cloud resource deletions Time Series Anomaly
Description	This query generates the baseline pattern of cloud resource deletions by an individual and generates an anomaly when any unusual spike is detected. These anomalies from unusual or privileged users could be an indication of a cloud infrastructure takedown by an adversary.
Severity	Medium
Tactics	Impact
Techniques	T1485
Required data connectors	AzureActivity
Kind	Scheduled
Query frequency	1d
Query period	14d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Activity/Analytic Rules/TimeSeriesAnomaly_Mass_Cloud_Resource_Deletions.yaml
Version	2.0.4
Arm template	ed43bdb7-eaab-4ea4-be52-6951fcfa7e3b.json

KQL

let starttime = 14d;
let endtime = 1d;
let timeframe = 1d;
let TotalEventsThreshold = 25;
let TimeSeriesData = AzureActivity 
| where TimeGenerated between (startofday(ago(starttime))..startofday(now())) 
| where OperationNameValue endswith "delete" 
| project TimeGenerated, Caller 
| make-series Total = count() on TimeGenerated from startofday(ago(starttime)) to startofday(now()) step timeframe by Caller;
TimeSeriesData 
| extend (anomalies, score, baseline) = series_decompose_anomalies(Total, 3, -1, 'linefit') 
| mv-expand Total to typeof(double), TimeGenerated to typeof(datetime), anomalies to typeof(double), score to typeof(double), baseline to typeof(long) 
| where TimeGenerated >= startofday(ago(endtime)) 
| where anomalies > 0 
| project Caller, TimeGenerated, Total, baseline, anomalies, score 
| where Total > TotalEventsThreshold and baseline > 0 
| join (AzureActivity 
| where TimeGenerated > startofday(ago(endtime)) 
| where OperationNameValue endswith "delete" 
| summarize count(), make_set(OperationNameValue,100), make_set(_ResourceId,100) by bin(TimeGenerated, timeframe), Caller ) on TimeGenerated, Caller 
| extend Name = iif(Caller has '@',tostring(split(Caller,'@',0)[0]),"")
| extend UPNSuffix = iif(Caller has '@',tostring(split(Caller,'@',1)[0]),"")
| extend AadUserId = iif(Caller !has '@',Caller,"")

YAML

tactics:
- Impact
id: ed43bdb7-eaab-4ea4-be52-6951fcfa7e3b
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Activity/Analytic Rules/TimeSeriesAnomaly_Mass_Cloud_Resource_Deletions.yaml
version: 2.0.4
status: Available
description: |
    'This query generates the baseline pattern of cloud resource deletions by an individual and generates an anomaly when any unusual spike is detected. These anomalies from unusual or privileged users could be an indication of a cloud infrastructure takedown by an adversary.'
tags:
- DEV-0537
severity: Medium
triggerThreshold: 0
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: Caller
  - identifier: Name
    columnName: Name
  - identifier: UPNSuffix
    columnName: UPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: AadUserId
    columnName: AadUserId
  entityType: Account
kind: Scheduled
name: Mass Cloud resource deletions Time Series Anomaly
query: |
  let starttime = 14d;
  let endtime = 1d;
  let timeframe = 1d;
  let TotalEventsThreshold = 25;
  let TimeSeriesData = AzureActivity 
  | where TimeGenerated between (startofday(ago(starttime))..startofday(now())) 
  | where OperationNameValue endswith "delete" 
  | project TimeGenerated, Caller 
  | make-series Total = count() on TimeGenerated from startofday(ago(starttime)) to startofday(now()) step timeframe by Caller;
  TimeSeriesData 
  | extend (anomalies, score, baseline) = series_decompose_anomalies(Total, 3, -1, 'linefit') 
  | mv-expand Total to typeof(double), TimeGenerated to typeof(datetime), anomalies to typeof(double), score to typeof(double), baseline to typeof(long) 
  | where TimeGenerated >= startofday(ago(endtime)) 
  | where anomalies > 0 
  | project Caller, TimeGenerated, Total, baseline, anomalies, score 
  | where Total > TotalEventsThreshold and baseline > 0 
  | join (AzureActivity 
  | where TimeGenerated > startofday(ago(endtime)) 
  | where OperationNameValue endswith "delete" 
  | summarize count(), make_set(OperationNameValue,100), make_set(_ResourceId,100) by bin(TimeGenerated, timeframe), Caller ) on TimeGenerated, Caller 
  | extend Name = iif(Caller has '@',tostring(split(Caller,'@',0)[0]),"")
  | extend UPNSuffix = iif(Caller has '@',tostring(split(Caller,'@',1)[0]),"")
  | extend AadUserId = iif(Caller !has '@',Caller,"")  
queryPeriod: 14d
queryFrequency: 1d
triggerOperator: gt
requiredDataConnectors:
- connectorId: AzureActivity
  dataTypes:
  - AzureActivity
relevantTechniques:
- T1485

ARM