Port Scan

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Id	b2c5907b-1040-4692-9802-9946031017e8
Rulename	Port Scan
Description	Identifies a source IP scanning multiple open ports on Azure Firewall. This can indicate malicious scanning of ports by an attacker, trying to reveal open ports in the organization that can be compromised for initial access. Configurable Parameters: - Port scan time - the time range to look for multiple ports scanned. Default is set to 30 seconds. - Minimum different ports threshold - alert only if more than this number of ports scanned. Default is set to 100.
Severity	Medium
Tactics	Discovery
Techniques	T1046
Required data connectors	AzureFirewall
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	1
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Firewall/Analytic Rules/Azure Firewall - Port Scan.yaml
Version	1.1.2
Arm template	b2c5907b-1040-4692-9802-9946031017e8.json

KQL

let MinimumDifferentPortsThreshold = 100;
let BinTime = 30s;
union isfuzzy=true(
AZFWApplicationRule
| summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn
| where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold),
(AZFWNetworkRule
| extend Fqdn = DestinationIp
| summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn
| where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold),
(AzureDiagnostics
| where OperationName == "AzureFirewallApplicationRuleLog" or OperationName == "AzureFirewallNetworkRuleLog"
| parse msg_s with * "from " SourceIp ":" SourcePort:int " to " Fqdn ":" DestinationPort:int *
| where isnotempty(Fqdn) and isnotempty(SourceIp)
| summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn
| where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold)

YAML

id: b2c5907b-1040-4692-9802-9946031017e8
tactics:
- Discovery
queryPeriod: 1d
triggerThreshold: 1
name: Port Scan
query: |
  let MinimumDifferentPortsThreshold = 100;
  let BinTime = 30s;
  union isfuzzy=true(
  AZFWApplicationRule
  | summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn
  | where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold),
  (AZFWNetworkRule
  | extend Fqdn = DestinationIp
  | summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn
  | where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold),
  (AzureDiagnostics
  | where OperationName == "AzureFirewallApplicationRuleLog" or OperationName == "AzureFirewallNetworkRuleLog"
  | parse msg_s with * "from " SourceIp ":" SourcePort:int " to " Fqdn ":" DestinationPort:int *
  | where isnotempty(Fqdn) and isnotempty(SourceIp)
  | summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn
  | where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold)  
severity: Medium
triggerOperator: gt
kind: Scheduled
relevantTechniques:
- T1046
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Firewall/Analytic Rules/Azure Firewall - Port Scan.yaml
queryFrequency: 1d
requiredDataConnectors:
- connectorId: AzureFirewall
  dataTypes:
  - AzureDiagnostics
  - AZFWApplicationRule
  - AZFWNetworkRule
description: |
  'Identifies a source IP scanning multiple open ports on Azure Firewall. This can indicate malicious scanning of ports by an attacker, trying to reveal open ports in the organization that can be compromised for initial access.

  Configurable Parameters:

  - Port scan time - the time range to look for multiple ports scanned. Default is set to 30 seconds.
  - Minimum different ports threshold - alert only if more than this number of ports scanned. Default is set to 100.'  
status: Available
version: 1.1.2
entityMappings:
- fieldMappings:
  - columnName: SourceIp
    identifier: Address
  entityType: IP
- fieldMappings:
  - columnName: Fqdn
    identifier: Url
  entityType: URL

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/b2c5907b-1040-4692-9802-9946031017e8')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/b2c5907b-1040-4692-9802-9946031017e8')]",
      "properties": {
        "alertRuleTemplateName": "b2c5907b-1040-4692-9802-9946031017e8",
        "customDetails": null,
        "description": "'Identifies a source IP scanning multiple open ports on Azure Firewall. This can indicate malicious scanning of ports by an attacker, trying to reveal open ports in the organization that can be compromised for initial access.\n\nConfigurable Parameters:\n\n- Port scan time - the time range to look for multiple ports scanned. Default is set to 30 seconds.\n- Minimum different ports threshold - alert only if more than this number of ports scanned. Default is set to 100.'\n",
        "displayName": "Port Scan",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SourceIp",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Fqdn",
                "identifier": "Url"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Firewall/Analytic Rules/Azure Firewall - Port Scan.yaml",
        "query": "let MinimumDifferentPortsThreshold = 100;\nlet BinTime = 30s;\nunion isfuzzy=true(\nAZFWApplicationRule\n| summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn\n| where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold),\n(AZFWNetworkRule\n| extend Fqdn = DestinationIp\n| summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn\n| where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold),\n(AzureDiagnostics\n| where OperationName == \"AzureFirewallApplicationRuleLog\" or OperationName == \"AzureFirewallNetworkRuleLog\"\n| parse msg_s with * \"from \" SourceIp \":\" SourcePort:int \" to \" Fqdn \":\" DestinationPort:int *\n| where isnotempty(Fqdn) and isnotempty(SourceIp)\n| summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn\n| where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold)\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Discovery"
        ],
        "techniques": [
          "T1046"
        ],
        "templateVersion": "1.1.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 1
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}