Ubiquiti - Large ICMP to external server

UbiquitiAuditEvent
| where EventCategory =~ 'firewall'
| where ipv4_is_private(SrcIpAddr)
| where ipv4_is_private(DstIpAddr) == 'False'
| where NetworkProtocol =~ 'ICMP'
| summarize avg_packet_length = avg(toint(NetworkBytes))
| extend a = 1
| join (UbiquitiAuditEvent
  | where EventCategory =~ 'firewall'
  | where ipv4_is_private(SrcIpAddr)
  | where ipv4_is_private(DstIpAddr) == 'False'
  | where NetworkProtocol =~ 'ICMP'
  | extend a = 1) on a
| where toint(NetworkBytes) > 2*avg_packet_length
| extend IPCustomEntity = SrcIpAddr

id: 6df85d74-e32f-4b71-80e5-bfe2af00be1c
triggerThreshold: 0
description: |
  'Detects large ICMP packets to external host.'
tactics:
- Exfiltration
- CommandAndControl
kind: Scheduled
queryPeriod: 14d
name: Ubiquiti - Large ICMP to external server
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Ubiquiti%20UniFi/Analytic%20Rules/UbiquitiL2RLargeIcmp.yaml
version: 1.0.2
queryFrequency: 1h
query: |
  UbiquitiAuditEvent
  | where EventCategory =~ 'firewall'
  | where ipv4_is_private(SrcIpAddr)
  | where ipv4_is_private(DstIpAddr) == 'False'
  | where NetworkProtocol =~ 'ICMP'
  | summarize avg_packet_length = avg(toint(NetworkBytes))
  | extend a = 1
  | join (UbiquitiAuditEvent
    | where EventCategory =~ 'firewall'
    | where ipv4_is_private(SrcIpAddr)
    | where ipv4_is_private(DstIpAddr) == 'False'
    | where NetworkProtocol =~ 'ICMP'
    | extend a = 1) on a
  | where toint(NetworkBytes) > 2*avg_packet_length
  | extend IPCustomEntity = SrcIpAddr
entityMappings:
- fieldMappings:
  - columnName: IPCustomEntity
    identifier: Address
  entityType: IP
severity: Medium
requiredDataConnectors:
- connectorId: CustomLogsAma
  dataTypes:
  - Ubiquiti_CL
triggerOperator: gt
status: Available
relevantTechniques:
- T1041
- T1572

{
  "$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/6df85d74-e32f-4b71-80e5-bfe2af00be1c')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/6df85d74-e32f-4b71-80e5-bfe2af00be1c')]",
      "properties": {
        "alertRuleTemplateName": "6df85d74-e32f-4b71-80e5-bfe2af00be1c",
        "customDetails": null,
        "description": "'Detects large ICMP packets to external host.'\n",
        "displayName": "Ubiquiti - Large ICMP to external server",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IPCustomEntity",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Ubiquiti%20UniFi/Analytic%20Rules/UbiquitiL2RLargeIcmp.yaml",
        "query": "UbiquitiAuditEvent\n| where EventCategory =~ 'firewall'\n| where ipv4_is_private(SrcIpAddr)\n| where ipv4_is_private(DstIpAddr) == 'False'\n| where NetworkProtocol =~ 'ICMP'\n| summarize avg_packet_length = avg(toint(NetworkBytes))\n| extend a = 1\n| join (UbiquitiAuditEvent\n  | where EventCategory =~ 'firewall'\n  | where ipv4_is_private(SrcIpAddr)\n  | where ipv4_is_private(DstIpAddr) == 'False'\n  | where NetworkProtocol =~ 'ICMP'\n  | extend a = 1) on a\n| where toint(NetworkBytes) > 2*avg_packet_length\n| extend IPCustomEntity = SrcIpAddr\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl",
          "Exfiltration"
        ],
        "techniques": [
          "T1041",
          "T1572"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}