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	2.0.2
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

OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Activity/Analytic Rules/TimeSeriesAnomaly_Mass_Cloud_Resource_Deletions.yaml
entityMappings:
- fieldMappings:
  - identifier: Name
    columnName: Name
  - identifier: UPNSuffix
    columnName: UPNSuffix
  - identifier: AadUserId
    columnName: AadUserId
  entityType: Account
kind: Scheduled
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,"")  
triggerOperator: gt
version: 2.0.2
queryPeriod: 14d
name: Mass Cloud resource deletions Time Series Anomaly
severity: Medium
relevantTechniques:
- T1485
requiredDataConnectors:
- dataTypes:
  - AzureActivity
  connectorId: AzureActivity
triggerThreshold: 0
tactics:
- Impact
queryFrequency: 1d
tags:
- DEV-0537
id: ed43bdb7-eaab-4ea4-be52-6951fcfa7e3b
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.'

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/ed43bdb7-eaab-4ea4-be52-6951fcfa7e3b')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/ed43bdb7-eaab-4ea4-be52-6951fcfa7e3b')]",
      "properties": {
        "alertRuleTemplateName": "ed43bdb7-eaab-4ea4-be52-6951fcfa7e3b",
        "customDetails": null,
        "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.'\n",
        "displayName": "Mass Cloud resource deletions Time Series Anomaly",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              },
              {
                "columnName": "AadUserId",
                "identifier": "AadUserId"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Activity/Analytic Rules/TimeSeriesAnomaly_Mass_Cloud_Resource_Deletions.yaml",
        "query": "let starttime = 14d;\nlet endtime = 1d;\nlet timeframe = 1d;\nlet TotalEventsThreshold = 25;\nlet TimeSeriesData = AzureActivity \n| where TimeGenerated between (startofday(ago(starttime))..startofday(now())) \n| where OperationNameValue endswith \"delete\" \n| project TimeGenerated, Caller \n| make-series Total = count() on TimeGenerated from startofday(ago(starttime)) to startofday(now()) step timeframe by Caller;\nTimeSeriesData \n| extend (anomalies, score, baseline) = series_decompose_anomalies(Total, 3, -1, 'linefit') \n| mv-expand Total to typeof(double), TimeGenerated to typeof(datetime), anomalies to typeof(double), score to typeof(double), baseline to typeof(long) \n| where TimeGenerated >= startofday(ago(endtime)) \n| where anomalies > 0 \n| project Caller, TimeGenerated, Total, baseline, anomalies, score \n| where Total > TotalEventsThreshold and baseline > 0 \n| join (AzureActivity \n| where TimeGenerated > startofday(ago(endtime)) \n| where OperationNameValue endswith \"delete\" \n| summarize count(), make_set(OperationNameValue,100), make_set(_ResourceId,100) by bin(TimeGenerated, timeframe), Caller ) on TimeGenerated, Caller \n| extend Name = iif(Caller has '@',tostring(split(Caller,'@',0)[0]),\"\")\n| extend UPNSuffix = iif(Caller has '@',tostring(split(Caller,'@',1)[0]),\"\")\n| extend AadUserId = iif(Caller !has '@',Caller,\"\")\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "status": "Available",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "tags": [
          "DEV-0537"
        ],
        "techniques": [
          "T1485"
        ],
        "templateVersion": "2.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}