CYFIRMA - Attack Surface - Open Ports Medium Rule | Microsoft Sentinel Analytic Rules

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Id	9e18b6c3-d172-4bc6-a7d9-cc7b0a03a69e
Rulename	CYFIRMA - Attack Surface - Open Ports Medium Rule
Description	“This rule is triggered when CYFIRMA identifies open and publicly accessible ports on internet-facing assets. Exposed services may include SSH, RDP, HTTP, or other potentially sensitive ports, increasing the risk of unauthorized access, exploitation, or reconnaissance by threat actors. Monitoring open ports is critical to reducing the external attack surface and preventing misuse through brute force, service vulnerabilities, or protocol exploitation.”
Severity	Medium
Tactics	InitialAccess CommandAndControl Discovery DefenseEvasion Persistence
Techniques	T1566 T1071 T1505
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/ASOpenPortsMediumRule.yaml
Version	1.0.1
Arm template	9e18b6c3-d172-4bc6-a7d9-cc7b0a03a69e.json

KQL

// Medium Severity - Open Ports Exposure Detected
let timeFrame = 5m;
CyfirmaASOpenPortsAlerts_CL
| where severity == 'High' and TimeGenerated between (ago(timeFrame) .. now())
| extend 
    Description=description, 
    FirstSeen=first_seen, 
    LastSeen=last_seen, 
    RiskScore=risk_score, 
    Domain=sub_domain, 
    TopDomain=top_domain, 
    NetworkIP=ip, 
    AlertUID=alert_uid, 
    UID=uid, 
    WebServer=web_server, 
    WebServerVersion=web_server_version, 
    OpenPorts=open_ports, 
    ProviderName='CYFIRMA', 
    ProductName='DeCYFIR/DeTCT'
| project
    TimeGenerated,
    Description,
    Domain,
    TopDomain,
    RiskScore,
    FirstSeen,
    LastSeen,
    NetworkIP,
    AlertUID,
    UID,
    WebServer,
    WebServerVersion,
    OpenPorts,
    ProductName,
    ProviderName

YAML

incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    lookbackDuration: PT5H
    reopenClosedIncident: false
    enabled: false
    matchingMethod: AllEntities
entityMappings:
- entityType: DNS
  fieldMappings:
  - columnName: Domain
    identifier: DomainName
- entityType: Host
  fieldMappings:
  - columnName: TopDomain
    identifier: HostName
  - columnName: Domain
    identifier: DnsDomain
- entityType: IP
  fieldMappings:
  - columnName: NetworkIP
    identifier: Address
query: |
  // Medium Severity - Open Ports Exposure Detected
  let timeFrame = 5m;
  CyfirmaASOpenPortsAlerts_CL
  | where severity == 'High' and TimeGenerated between (ago(timeFrame) .. now())
  | extend 
      Description=description, 
      FirstSeen=first_seen, 
      LastSeen=last_seen, 
      RiskScore=risk_score, 
      Domain=sub_domain, 
      TopDomain=top_domain, 
      NetworkIP=ip, 
      AlertUID=alert_uid, 
      UID=uid, 
      WebServer=web_server, 
      WebServerVersion=web_server_version, 
      OpenPorts=open_ports, 
      ProviderName='CYFIRMA', 
      ProductName='DeCYFIR/DeTCT'
  | project
      TimeGenerated,
      Description,
      Domain,
      TopDomain,
      RiskScore,
      FirstSeen,
      LastSeen,
      NetworkIP,
      AlertUID,
      UID,
      WebServer,
      WebServerVersion,
      OpenPorts,
      ProductName,
      ProviderName
eventGroupingSettings:
  aggregationKind: AlertPerResult
id: 9e18b6c3-d172-4bc6-a7d9-cc7b0a03a69e
queryFrequency: 5m
alertDetailsOverride:
  alertDisplayNameFormat: 'CYFIRMA - Medium Severity Open Ports Exposure Detected on Assets - Domain: {{Domain}}, IP: {{NetworkIP}}'
  alertDescriptionFormat: CYFIRMA - Medium Severity Open Ports Exposure Detected on Assets - {{Description}}
  alertDynamicProperties:
  - value: DeCYFIR/DeTCT
    alertProperty: ProductName
  - value: CYFIRMA
    alertProperty: ProviderName
status: Available
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cyfirma%20Attack%20Surface/Analytic%20Rules/ASOpenPortsMediumRule.yaml
severity: Medium
relevantTechniques:
- T1566
- T1071
- T1505
version: 1.0.1
kind: Scheduled
tactics:
- InitialAccess
- CommandAndControl
- Discovery
- DefenseEvasion
- Persistence
requiredDataConnectors:
- dataTypes:
  - CyfirmaASOpenPortsAlerts_CL
  connectorId: CyfirmaAttackSurfaceAlertsConnector
description: |
  "This rule is triggered when CYFIRMA identifies open and publicly accessible ports on internet-facing assets. Exposed services may include SSH, RDP, HTTP, or other potentially sensitive ports, increasing the risk of unauthorized access, exploitation, or reconnaissance by threat actors. Monitoring open ports is critical to reducing the external attack surface and preventing misuse through brute force, service vulnerabilities, or protocol exploitation."
customDetails:
  OpenPorts: OpenPorts
  Description: Description
  TimeGenerated: TimeGenerated
  UID: UID
  LastSeen: LastSeen
  FirstSeen: FirstSeen
  AlertUID: AlertUID
  RiskScore: RiskScore
  WebServer: WebServer
  WebServerVersion: WebServerVersion
triggerOperator: gt
name: CYFIRMA - Attack Surface - Open Ports Medium Rule
triggerThreshold: 0
queryPeriod: 5m

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/9e18b6c3-d172-4bc6-a7d9-cc7b0a03a69e')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/9e18b6c3-d172-4bc6-a7d9-cc7b0a03a69e')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "CYFIRMA - Medium Severity Open Ports Exposure Detected on Assets - {{Description}}",
          "alertDisplayNameFormat": "CYFIRMA - Medium Severity Open Ports Exposure Detected on Assets - Domain: {{Domain}}, IP: {{NetworkIP}}",
          "alertDynamicProperties": [
            {
              "alertProperty": "ProductName",
              "value": "DeCYFIR/DeTCT"
            },
            {
              "alertProperty": "ProviderName",
              "value": "CYFIRMA"
            }
          ]
        },
        "alertRuleTemplateName": "9e18b6c3-d172-4bc6-a7d9-cc7b0a03a69e",
        "customDetails": {
          "AlertUID": "AlertUID",
          "Description": "Description",
          "FirstSeen": "FirstSeen",
          "LastSeen": "LastSeen",
          "OpenPorts": "OpenPorts",
          "RiskScore": "RiskScore",
          "TimeGenerated": "TimeGenerated",
          "UID": "UID",
          "WebServer": "WebServer",
          "WebServerVersion": "WebServerVersion"
        },
        "description": "\"This rule is triggered when CYFIRMA identifies open and publicly accessible ports on internet-facing assets. Exposed services may include SSH, RDP, HTTP, or other potentially sensitive ports, increasing the risk of unauthorized access, exploitation, or reconnaissance by threat actors. Monitoring open ports is critical to reducing the external attack surface and preventing misuse through brute force, service vulnerabilities, or protocol exploitation.\"\n",
        "displayName": "CYFIRMA - Attack Surface - Open Ports Medium Rule",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "DNS",
            "fieldMappings": [
              {
                "columnName": "Domain",
                "identifier": "DomainName"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "TopDomain",
                "identifier": "HostName"
              },
              {
                "columnName": "Domain",
                "identifier": "DnsDomain"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "NetworkIP",
                "identifier": "Address"
              }
            ]
          }
        ],
        "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/ASOpenPortsMediumRule.yaml",
        "query": "// Medium Severity - Open Ports Exposure Detected\nlet timeFrame = 5m;\nCyfirmaASOpenPortsAlerts_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=sub_domain, \n    TopDomain=top_domain, \n    NetworkIP=ip, \n    AlertUID=alert_uid, \n    UID=uid, \n    WebServer=web_server, \n    WebServerVersion=web_server_version, \n    OpenPorts=open_ports, \n    ProviderName='CYFIRMA', \n    ProductName='DeCYFIR/DeTCT'\n| project\n    TimeGenerated,\n    Description,\n    Domain,\n    TopDomain,\n    RiskScore,\n    FirstSeen,\n    LastSeen,\n    NetworkIP,\n    AlertUID,\n    UID,\n    WebServer,\n    WebServerVersion,\n    OpenPorts,\n    ProductName,\n    ProviderName\n",
        "queryFrequency": "PT5M",
        "queryPeriod": "PT5M",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl",
          "DefenseEvasion",
          "Discovery",
          "InitialAccess",
          "Persistence"
        ],
        "techniques": [
          "T1071",
          "T1505",
          "T1566"
        ],
        "templateVersion": "1.0.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}