CYFIRMA - Attack Surface - Cloud Weakness High Rule | Microsoft Sentinel Analytic Rules

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Id	87cd8b10-90f6-4967-a4a7-2142e848ec8f
Rulename	CYFIRMA - Attack Surface - Cloud Weakness High Rule
Description	“This rule detects cloud storage buckets (e.g., AWS S3) that are publicly accessible without authentication. Such misconfigurations can lead to data exfiltration, compliance violations, and reputational damage. The detection is based on Cyfirma’s Attack Surface Intelligence.”
Severity	High
Tactics	InitialAccess Collection Discovery Exfiltration
Techniques	T1087 T1087.004
Required data connectors	CyfirmaAttackSurfaceAlertsConnector
Kind	Scheduled
Query frequency	5m
Query period	5m
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cyfirma%20Attack%20Surface/Analytic%20Rules/ASCloudWeaknessHighRule.yaml
Version	1.0.1
Arm template	87cd8b10-90f6-4967-a4a7-2142e848ec8f.json

KQL

// High Severity - Attack Surface - Cloud Weakness - Unauthorized Public Cloud Storage Exposure Detected
let timeFrame = 5m;
CyfirmaASCloudWeaknessAlerts_CL
| where severity == 'Critical' and TimeGenerated between (ago(timeFrame) .. now())
| extend
    Description=description,
    FirstSeen=first_seen,
    LastSeen=last_seen,
    RiskScore=risk_score,
    Domain=asset_name,
    AlertUID=alert_uid,
    UID=uid,
    Source=source,
    SourceType=source_type,
    CreatedDate=created_date,
    Impact=impact,
    ProviderName='CYFIRMA',
    ProductName='DeCYFIR/DeTCT'
| project
    TimeGenerated,
    Description,
    Domain,
    RiskScore,
    FirstSeen,
    LastSeen,
    AlertUID,
    UID,
    Source,
    SourceType,
    CreatedDate,
    Impact,
    ProviderName,
    ProductName

YAML

queryFrequency: 5m
entityMappings:
- fieldMappings:
  - columnName: Domain
    identifier: DomainName
  entityType: DNS
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    lookbackDuration: PT5H
    matchingMethod: AllEntities
    enabled: false
    reopenClosedIncident: false
triggerThreshold: 0
triggerOperator: gt
severity: High
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cyfirma%20Attack%20Surface/Analytic%20Rules/ASCloudWeaknessHighRule.yaml
eventGroupingSettings:
  aggregationKind: AlertPerResult
alertDetailsOverride:
  alertDisplayNameFormat: 'CYFIRMA - High Severity Alert - Unauthorized Public Cloud Storage Exposure Detected - Domain: {{Domain}} '
  alertDynamicProperties:
  - alertProperty: ProductName
    value: ProductName
  - alertProperty: ProviderName
    value: ProviderName
  alertDescriptionFormat: 'CYFIRMA - High Severity Alert - Unauthorized Public Cloud Storage Exposure Detected - {{Description}} '
query: |
  // High Severity - Attack Surface - Cloud Weakness - Unauthorized Public Cloud Storage Exposure Detected
  let timeFrame = 5m;
  CyfirmaASCloudWeaknessAlerts_CL
  | where severity == 'Critical' and TimeGenerated between (ago(timeFrame) .. now())
  | extend
      Description=description,
      FirstSeen=first_seen,
      LastSeen=last_seen,
      RiskScore=risk_score,
      Domain=asset_name,
      AlertUID=alert_uid,
      UID=uid,
      Source=source,
      SourceType=source_type,
      CreatedDate=created_date,
      Impact=impact,
      ProviderName='CYFIRMA',
      ProductName='DeCYFIR/DeTCT'
  | project
      TimeGenerated,
      Description,
      Domain,
      RiskScore,
      FirstSeen,
      LastSeen,
      AlertUID,
      UID,
      Source,
      SourceType,
      CreatedDate,
      Impact,
      ProviderName,
      ProductName
tactics:
- InitialAccess
- Collection
- Discovery
- Exfiltration
queryPeriod: 5m
customDetails:
  Source: Source
  TimeGenerated: TimeGenerated
  CreatedDate: CreatedDate
  Impact: Impact
  AlertUID: AlertUID
  FirstSeen: FirstSeen
  UID: UID
  RiskScore: RiskScore
  SourceType: SourceType
  LastSeen: LastSeen
relevantTechniques:
- T1087
- T1087.004
name: CYFIRMA - Attack Surface - Cloud Weakness High Rule
requiredDataConnectors:
- connectorId: CyfirmaAttackSurfaceAlertsConnector
  dataTypes:
  - CyfirmaASCloudWeaknessAlerts_CL
id: 87cd8b10-90f6-4967-a4a7-2142e848ec8f
version: 1.0.1
description: |
  "This rule detects cloud storage buckets (e.g., AWS S3) that are publicly accessible without authentication. 
  Such misconfigurations can lead to data exfiltration, compliance violations, and reputational damage. 
  The detection is based on Cyfirma's Attack Surface Intelligence."
kind: Scheduled
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": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/87cd8b10-90f6-4967-a4a7-2142e848ec8f')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/87cd8b10-90f6-4967-a4a7-2142e848ec8f')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "CYFIRMA - High Severity Alert - Unauthorized Public Cloud Storage Exposure Detected - {{Description}} ",
          "alertDisplayNameFormat": "CYFIRMA - High Severity Alert - Unauthorized Public Cloud Storage Exposure Detected - Domain: {{Domain}} ",
          "alertDynamicProperties": [
            {
              "alertProperty": "ProductName",
              "value": "ProductName"
            },
            {
              "alertProperty": "ProviderName",
              "value": "ProviderName"
            }
          ]
        },
        "alertRuleTemplateName": "87cd8b10-90f6-4967-a4a7-2142e848ec8f",
        "customDetails": {
          "AlertUID": "AlertUID",
          "CreatedDate": "CreatedDate",
          "FirstSeen": "FirstSeen",
          "Impact": "Impact",
          "LastSeen": "LastSeen",
          "RiskScore": "RiskScore",
          "Source": "Source",
          "SourceType": "SourceType",
          "TimeGenerated": "TimeGenerated",
          "UID": "UID"
        },
        "description": "\"This rule detects cloud storage buckets (e.g., AWS S3) that are publicly accessible without authentication. \nSuch misconfigurations can lead to data exfiltration, compliance violations, and reputational damage. \nThe detection is based on Cyfirma's Attack Surface Intelligence.\"\n",
        "displayName": "CYFIRMA - Attack Surface - Cloud Weakness High Rule",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "DNS",
            "fieldMappings": [
              {
                "columnName": "Domain",
                "identifier": "DomainName"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "AlertPerResult"
        },
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": false,
            "lookbackDuration": "PT5H",
            "matchingMethod": "AllEntities",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cyfirma%20Attack%20Surface/Analytic%20Rules/ASCloudWeaknessHighRule.yaml",
        "query": "// High Severity - Attack Surface - Cloud Weakness - Unauthorized Public Cloud Storage Exposure Detected\nlet timeFrame = 5m;\nCyfirmaASCloudWeaknessAlerts_CL\n| where severity == 'Critical' and TimeGenerated between (ago(timeFrame) .. now())\n| extend\n    Description=description,\n    FirstSeen=first_seen,\n    LastSeen=last_seen,\n    RiskScore=risk_score,\n    Domain=asset_name,\n    AlertUID=alert_uid,\n    UID=uid,\n    Source=source,\n    SourceType=source_type,\n    CreatedDate=created_date,\n    Impact=impact,\n    ProviderName='CYFIRMA',\n    ProductName='DeCYFIR/DeTCT'\n| project\n    TimeGenerated,\n    Description,\n    Domain,\n    RiskScore,\n    FirstSeen,\n    LastSeen,\n    AlertUID,\n    UID,\n    Source,\n    SourceType,\n    CreatedDate,\n    Impact,\n    ProviderName,\n    ProductName\n",
        "queryFrequency": "PT5M",
        "queryPeriod": "PT5M",
        "severity": "High",
        "status": "Available",
        "subTechniques": [
          "T1087.004"
        ],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Collection",
          "Discovery",
          "Exfiltration",
          "InitialAccess"
        ],
        "techniques": [
          "T1087"
        ],
        "templateVersion": "1.0.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}