Port Sweep | Microsoft Sentinel Analytic Rules

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Id	720335f4-ee8c-4270-9424-d0859222168c
Rulename	Port Sweep
Description	Identifies a source IP scanning same open ports on the Azure Firewall IPs. This can indicate malicious scanning of port by an attacker, trying to reveal IPs with specific ports open in the organization. The ports can be compromised by attackers for initial access, most often by exploiting vulnerability. Configurable Parameters: - Port sweep time - the time range to look for multiple hosts scanned. Default is set to 30 seconds. - Minimum different hosts threshold - alert only if more than this number of hosts scanned. Default is set to 200.
Severity	Medium
Tactics	Discovery Reconnaissance
Techniques	T1046 T1595.001
Required data connectors	AzureFirewall
Kind	Scheduled
Query frequency	1h
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure%20Firewall/Analytic%20Rules/Azure%20Firewall%20-%20Port%20Sweep.yaml
Version	1.2.3
Arm template	720335f4-ee8c-4270-9424-d0859222168c.json

KQL

let MinimumDifferentHostsThreshold = 200;
let ExcludedPorts = dynamic([80 , 443]);
let BinTime = 30s;
union isfuzzy=true(
AZFWApplicationRule
| where DestinationPort !in (ExcludedPorts)
| summarize AlertTimedCountHostsInBinTime = make_set(Fqdn) by SourceIp, bin(TimeGenerated, BinTime), DestinationPort
| where array_length(AlertTimedCountHostsInBinTime) > MinimumDifferentHostsThreshold
| mv-expand Fqdn = AlertTimedCountHostsInBinTime),
(AZFWNetworkRule
| extend Fqdn = DestinationIp
| where DestinationPort !in (ExcludedPorts)
| summarize AlertTimedCountHostsInBinTime = make_set(Fqdn) by SourceIp, bin(TimeGenerated, BinTime), DestinationPort
| where array_length(AlertTimedCountHostsInBinTime) > MinimumDifferentHostsThreshold
| mv-expand Fqdn = AlertTimedCountHostsInBinTime),
(AzureDiagnostics
| where OperationName == "AzureFirewallApplicationRuleLog" or OperationName == "AzureFirewallNetworkRuleLog"
| parse msg_s with * "from " SourceIp ":" SourcePort:int " to " Fqdn ":" DestinationPort:int ". " * "Action: " Action "." *
| where DestinationPort !in (ExcludedPorts)
| where isnotempty(Fqdn) and isnotempty(SourceIp) and isnotempty(DestinationPort)
| summarize AlertTimedCountHostsInBinTime = make_set(Fqdn) by SourceIp, bin(TimeGenerated, BinTime), DestinationPort
| where array_length(AlertTimedCountHostsInBinTime) > MinimumDifferentHostsThreshold
| mv-expand Fqdn = AlertTimedCountHostsInBinTime)
| project bin(TimeGenerated, BinTime), SourceIp, DestinationPort, AlertTimedCountHostsInBinTime, Fqdn

YAML

name: Port Sweep
triggerOperator: gt
triggerThreshold: 0
tactics:
- Discovery
- Reconnaissance
queryFrequency: 1h
alertDetailsOverride:
  alertDescriptionFormat: Source IP {{SourceIp}} has scanned {{AlertTimedCountHostsInBinTime}} different hosts on port {{DestinationPort}} within a short time frame, which may indicate reconnaissance activity.
  alertDisplayNameFormat: Port Sweep Detected from {{SourceIp}} on Port {{DestinationPort}}
query: |
  let MinimumDifferentHostsThreshold = 200;
  let ExcludedPorts = dynamic([80 , 443]);
  let BinTime = 30s;
  union isfuzzy=true(
  AZFWApplicationRule
  | where DestinationPort !in (ExcludedPorts)
  | summarize AlertTimedCountHostsInBinTime = make_set(Fqdn) by SourceIp, bin(TimeGenerated, BinTime), DestinationPort
  | where array_length(AlertTimedCountHostsInBinTime) > MinimumDifferentHostsThreshold
  | mv-expand Fqdn = AlertTimedCountHostsInBinTime),
  (AZFWNetworkRule
  | extend Fqdn = DestinationIp
  | where DestinationPort !in (ExcludedPorts)
  | summarize AlertTimedCountHostsInBinTime = make_set(Fqdn) by SourceIp, bin(TimeGenerated, BinTime), DestinationPort
  | where array_length(AlertTimedCountHostsInBinTime) > MinimumDifferentHostsThreshold
  | mv-expand Fqdn = AlertTimedCountHostsInBinTime),
  (AzureDiagnostics
  | where OperationName == "AzureFirewallApplicationRuleLog" or OperationName == "AzureFirewallNetworkRuleLog"
  | parse msg_s with * "from " SourceIp ":" SourcePort:int " to " Fqdn ":" DestinationPort:int ". " * "Action: " Action "." *
  | where DestinationPort !in (ExcludedPorts)
  | where isnotempty(Fqdn) and isnotempty(SourceIp) and isnotempty(DestinationPort)
  | summarize AlertTimedCountHostsInBinTime = make_set(Fqdn) by SourceIp, bin(TimeGenerated, BinTime), DestinationPort
  | where array_length(AlertTimedCountHostsInBinTime) > MinimumDifferentHostsThreshold
  | mv-expand Fqdn = AlertTimedCountHostsInBinTime)
  | project bin(TimeGenerated, BinTime), SourceIp, DestinationPort, AlertTimedCountHostsInBinTime, Fqdn
customDetails:
  DestinationPort: DestinationPort
id: 720335f4-ee8c-4270-9424-d0859222168c
kind: Scheduled
description: |
  'Identifies a source IP scanning same open ports on the Azure Firewall IPs. This can indicate malicious scanning of port by an attacker, trying to reveal IPs with specific ports open in the organization. The ports can be compromised by attackers for initial access, most often by exploiting vulnerability.

  Configurable Parameters:

  - Port sweep time - the time range to look for multiple hosts scanned. Default is set to 30 seconds.
  - Minimum different hosts threshold - alert only if more than this number of hosts scanned. Default is set to 200.'
severity: Medium
relevantTechniques:
- T1046
- T1595.001
entityMappings:
- fieldMappings:
  - columnName: SourceIp
    identifier: Address
  entityType: IP
- fieldMappings:
  - columnName: Fqdn
    identifier: Url
  entityType: URL
requiredDataConnectors:
- connectorId: AzureFirewall
  dataTypes:
  - AzureDiagnostics
  - AZFWApplicationRule
  - AZFWNetworkRule
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure%20Firewall/Analytic%20Rules/Azure%20Firewall%20-%20Port%20Sweep.yaml
status: Available
version: 1.2.3
queryPeriod: 1d

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/720335f4-ee8c-4270-9424-d0859222168c')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/720335f4-ee8c-4270-9424-d0859222168c')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "Source IP {{SourceIp}} has scanned {{AlertTimedCountHostsInBinTime}} different hosts on port {{DestinationPort}} within a short time frame, which may indicate reconnaissance activity.",
          "alertDisplayNameFormat": "Port Sweep Detected from {{SourceIp}} on Port {{DestinationPort}}"
        },
        "alertRuleTemplateName": "720335f4-ee8c-4270-9424-d0859222168c",
        "customDetails": {
          "DestinationPort": "DestinationPort"
        },
        "description": "'Identifies a source IP scanning same open ports on the Azure Firewall IPs. This can indicate malicious scanning of port by an attacker, trying to reveal IPs with specific ports open in the organization. The ports can be compromised by attackers for initial access, most often by exploiting vulnerability.\n\nConfigurable Parameters:\n\n- Port sweep time - the time range to look for multiple hosts scanned. Default is set to 30 seconds.\n- Minimum different hosts threshold - alert only if more than this number of hosts scanned. Default is set to 200.'\n",
        "displayName": "Port Sweep",
        "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%20Firewall/Analytic%20Rules/Azure%20Firewall%20-%20Port%20Sweep.yaml",
        "query": "let MinimumDifferentHostsThreshold = 200;\nlet ExcludedPorts = dynamic([80 , 443]);\nlet BinTime = 30s;\nunion isfuzzy=true(\nAZFWApplicationRule\n| where DestinationPort !in (ExcludedPorts)\n| summarize AlertTimedCountHostsInBinTime = make_set(Fqdn) by SourceIp, bin(TimeGenerated, BinTime), DestinationPort\n| where array_length(AlertTimedCountHostsInBinTime) > MinimumDifferentHostsThreshold\n| mv-expand Fqdn = AlertTimedCountHostsInBinTime),\n(AZFWNetworkRule\n| extend Fqdn = DestinationIp\n| where DestinationPort !in (ExcludedPorts)\n| summarize AlertTimedCountHostsInBinTime = make_set(Fqdn) by SourceIp, bin(TimeGenerated, BinTime), DestinationPort\n| where array_length(AlertTimedCountHostsInBinTime) > MinimumDifferentHostsThreshold\n| mv-expand Fqdn = AlertTimedCountHostsInBinTime),\n(AzureDiagnostics\n| where OperationName == \"AzureFirewallApplicationRuleLog\" or OperationName == \"AzureFirewallNetworkRuleLog\"\n| parse msg_s with * \"from \" SourceIp \":\" SourcePort:int \" to \" Fqdn \":\" DestinationPort:int \". \" * \"Action: \" Action \".\" *\n| where DestinationPort !in (ExcludedPorts)\n| where isnotempty(Fqdn) and isnotempty(SourceIp) and isnotempty(DestinationPort)\n| summarize AlertTimedCountHostsInBinTime = make_set(Fqdn) by SourceIp, bin(TimeGenerated, BinTime), DestinationPort\n| where array_length(AlertTimedCountHostsInBinTime) > MinimumDifferentHostsThreshold\n| mv-expand Fqdn = AlertTimedCountHostsInBinTime)\n| project bin(TimeGenerated, BinTime), SourceIp, DestinationPort, AlertTimedCountHostsInBinTime, Fqdn\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P1D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [
          "T1595.001"
        ],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Discovery",
          "Reconnaissance"
        ],
        "techniques": [
          "T1046",
          "T1595"
        ],
        "templateVersion": "1.2.3",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}