Threat Essentials - Mass Cloud resource deletions Time Series Anomaly

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Id	fa2658fe-3714-4c55-bb12-2b7275c628e8
Rulename	Threat Essentials - Mass Cloud resource deletions Time Series Anomaly
Description	This query generates baseline pattern of cloud resource deletions by an user and generated anomaly when any unusual spike is detected. These anomalies from unusual or privileged users could be an indication of cloud infrastructure take-down 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/SecurityThreatEssentialSolution/Analytic Rules/Threat_Essentials_TimeSeriesAnomaly_Mass_Cloud_Resource_Deletions.yaml
Version	1.0.1
Arm template	fa2658fe-3714-4c55-bb12-2b7275c628e8.json

KQL

let starttime = 14d;
let endtime = 1d;
let timeframe = 1h;
let TotalEventsThreshold = 25; 
let TimeSeriesData = 
AzureActivity 
| where TimeGenerated between (startofday(ago(starttime))..startofday(ago(endtime)))
| where OperationNameValue endswith "delete" 
| project TimeGenerated, Caller 
| make-series Total = count() on TimeGenerated from startofday(ago(starttime)) to startofday(ago(endtime)) step timeframe by Caller; 
let TimeSeriesAlerts = materialize(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 anomalies > 0 
| project Caller, TimeGenerated, Total, baseline, anomalies, score 
| where Total > TotalEventsThreshold and baseline > 0 ); 
TimeSeriesAlerts 
| where TimeGenerated > (ago(endtime)) 
| project TimeGenerated, Caller 
| join kind = inner (AzureActivity 
| where TimeGenerated > (ago(endtime)) 
| where OperationNameValue endswith "delete" 
| summarize count(), make_set(OperationNameValue), make_set(Resource) by bin(TimeGenerated, 1h), 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

id: fa2658fe-3714-4c55-bb12-2b7275c628e8
requiredDataConnectors:
- dataTypes:
  - AzureActivity
  connectorId: AzureActivity
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/SecurityThreatEssentialSolution/Analytic Rules/Threat_Essentials_TimeSeriesAnomaly_Mass_Cloud_Resource_Deletions.yaml
relevantTechniques:
- T1485
kind: Scheduled
name: Threat Essentials - Mass Cloud resource deletions Time Series Anomaly
queryFrequency: 1d
query: |
  let starttime = 14d;
  let endtime = 1d;
  let timeframe = 1h;
  let TotalEventsThreshold = 25; 
  let TimeSeriesData = 
  AzureActivity 
  | where TimeGenerated between (startofday(ago(starttime))..startofday(ago(endtime)))
  | where OperationNameValue endswith "delete" 
  | project TimeGenerated, Caller 
  | make-series Total = count() on TimeGenerated from startofday(ago(starttime)) to startofday(ago(endtime)) step timeframe by Caller; 
  let TimeSeriesAlerts = materialize(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 anomalies > 0 
  | project Caller, TimeGenerated, Total, baseline, anomalies, score 
  | where Total > TotalEventsThreshold and baseline > 0 ); 
  TimeSeriesAlerts 
  | where TimeGenerated > (ago(endtime)) 
  | project TimeGenerated, Caller 
  | join kind = inner (AzureActivity 
  | where TimeGenerated > (ago(endtime)) 
  | where OperationNameValue endswith "delete" 
  | summarize count(), make_set(OperationNameValue), make_set(Resource) by bin(TimeGenerated, 1h), 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,"")  
severity: Medium
tags:
- DEV-0537
triggerThreshold: 0
tactics:
- Impact
entityMappings:
- fieldMappings:
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
  - columnName: AadUserId
    identifier: AadUserId
  entityType: Account
version: 1.0.1
queryPeriod: 14d
description: |
  'This query generates baseline pattern of cloud resource deletions by an user and generated anomaly 
  when any unusual spike is detected.
  These anomalies from unusual or privileged users could be an indication of cloud infrastructure 
  take-down by an adversary '  
status: Available

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/fa2658fe-3714-4c55-bb12-2b7275c628e8')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/fa2658fe-3714-4c55-bb12-2b7275c628e8')]",
      "properties": {
        "alertRuleTemplateName": "fa2658fe-3714-4c55-bb12-2b7275c628e8",
        "customDetails": null,
        "description": "'This query generates baseline pattern of cloud resource deletions by an user and generated anomaly \nwhen any unusual spike is detected.\nThese anomalies from unusual or privileged users could be an indication of cloud infrastructure \ntake-down by an adversary '\n",
        "displayName": "Threat Essentials - 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/SecurityThreatEssentialSolution/Analytic Rules/Threat_Essentials_TimeSeriesAnomaly_Mass_Cloud_Resource_Deletions.yaml",
        "query": "let starttime = 14d;\nlet endtime = 1d;\nlet timeframe = 1h;\nlet TotalEventsThreshold = 25; \nlet TimeSeriesData = \nAzureActivity \n| where TimeGenerated between (startofday(ago(starttime))..startofday(ago(endtime)))\n| where OperationNameValue endswith \"delete\" \n| project TimeGenerated, Caller \n| make-series Total = count() on TimeGenerated from startofday(ago(starttime)) to startofday(ago(endtime)) step timeframe by Caller; \nlet TimeSeriesAlerts = materialize(TimeSeriesData \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 anomalies > 0 \n| project Caller, TimeGenerated, Total, baseline, anomalies, score \n| where Total > TotalEventsThreshold and baseline > 0 ); \nTimeSeriesAlerts \n| where TimeGenerated > (ago(endtime)) \n| project TimeGenerated, Caller \n| join kind = inner (AzureActivity \n| where TimeGenerated > (ago(endtime)) \n| where OperationNameValue endswith \"delete\" \n| summarize count(), make_set(OperationNameValue), make_set(Resource) by bin(TimeGenerated, 1h), 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": "1.0.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}