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

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Id	b8a3c5e2-04d5-4b61-9b62-b4f53a417f74
Rulename	CYFIRMA - Attack Surface - Cloud Weakness Medium 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	Medium
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/ASCloudWeaknessMediumRule.yaml
Version	1.0.1
Arm template	b8a3c5e2-04d5-4b61-9b62-b4f53a417f74.json

KQL

// Medium Severity - Attack Surface - Cloud Weakness - Unauthorized Public Cloud Storage Exposure Detected
let timeFrame = 5m;
CyfirmaASCloudWeaknessAlerts_CL
| where severity == 'High' 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

relevantTechniques:
- T1087
- T1087.004
incidentConfiguration:
  groupingConfiguration:
    reopenClosedIncident: false
    lookbackDuration: PT5H
    matchingMethod: AllEntities
    enabled: false
  createIncident: true
customDetails:
  FirstSeen: FirstSeen
  CreatedDate: CreatedDate
  Source: Source
  UID: UID
  Impact: Impact
  AlertUID: AlertUID
  LastSeen: LastSeen
  TimeGenerated: TimeGenerated
  SourceType: SourceType
  RiskScore: RiskScore
queryFrequency: 5m
queryPeriod: 5m
triggerOperator: gt
severity: Medium
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."
status: Available
id: b8a3c5e2-04d5-4b61-9b62-b4f53a417f74
query: |
  // Medium Severity - Attack Surface - Cloud Weakness - Unauthorized Public Cloud Storage Exposure Detected
  let timeFrame = 5m;
  CyfirmaASCloudWeaknessAlerts_CL
  | where severity == 'High' 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
requiredDataConnectors:
- connectorId: CyfirmaAttackSurfaceAlertsConnector
  dataTypes:
  - CyfirmaASCloudWeaknessAlerts_CL
version: 1.0.1
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cyfirma%20Attack%20Surface/Analytic%20Rules/ASCloudWeaknessMediumRule.yaml
name: CYFIRMA - Attack Surface - Cloud Weakness Medium Rule
tactics:
- InitialAccess
- Collection
- Discovery
- Exfiltration
entityMappings:
- entityType: DNS
  fieldMappings:
  - columnName: Domain
    identifier: DomainName
kind: Scheduled
alertDetailsOverride:
  alertDescriptionFormat: CYFIRMA - Medium Severity Alert - Unauthorized Public Cloud Storage Exposure Detected - {{Description}}
  alertDynamicProperties:
  - value: ProductName
    alertProperty: ProductName
  - value: ProviderName
    alertProperty: ProviderName
  alertDisplayNameFormat: 'CYFIRMA - Medium Severity Alert - Unauthorized Public Cloud Storage Exposure Detected - Domain: {{Domain}}'
triggerThreshold: 0
eventGroupingSettings:
  aggregationKind: AlertPerResult

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/b8a3c5e2-04d5-4b61-9b62-b4f53a417f74')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/b8a3c5e2-04d5-4b61-9b62-b4f53a417f74')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "CYFIRMA - Medium Severity Alert - Unauthorized Public Cloud Storage Exposure Detected - {{Description}}",
          "alertDisplayNameFormat": "CYFIRMA - Medium Severity Alert - Unauthorized Public Cloud Storage Exposure Detected - Domain: {{Domain}}",
          "alertDynamicProperties": [
            {
              "alertProperty": "ProductName",
              "value": "ProductName"
            },
            {
              "alertProperty": "ProviderName",
              "value": "ProviderName"
            }
          ]
        },
        "alertRuleTemplateName": "b8a3c5e2-04d5-4b61-9b62-b4f53a417f74",
        "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 Medium 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/ASCloudWeaknessMediumRule.yaml",
        "query": "// Medium Severity - Attack Surface - Cloud Weakness - Unauthorized Public Cloud Storage Exposure Detected\nlet timeFrame = 5m;\nCyfirmaASCloudWeaknessAlerts_CL\n| where severity == 'High' 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": "Medium",
        "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"
    }
  ]
}