NGINX - Multiple user agents for single source

let threshold = 5;
NGINXHTTPServer
| summarize makeset(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 5m)
| extend ua_count = array_length(set_HttpUserAgentOriginal)
| where ua_count > threshold
| extend IPCustomEntity = SrcIpAddr

tactics:
- InitialAccess
name: NGINX - Multiple user agents for single source
id: 83a0b48f-1cb7-4b4f-a018-23c3203a239b
requiredDataConnectors:
- connectorId: CustomLogsAma
  dataTypes:
  - NGINX_CL
query: |
  let threshold = 5;
  NGINXHTTPServer
  | summarize makeset(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 5m)
  | extend ua_count = array_length(set_HttpUserAgentOriginal)
  | where ua_count > threshold
  | extend IPCustomEntity = SrcIpAddr  
relevantTechniques:
- T1190
- T1133
description: |
    'Detects requests with different user agents from one source in short timeframe.'
triggerOperator: gt
queryPeriod: 1h
severity: Medium
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: IPCustomEntity
  entityType: IP
version: 1.0.2
triggerThreshold: 0
kind: Scheduled
queryFrequency: 1h
status: Available
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/NGINX HTTP Server/Analytic Rules/NGINXDifferentUAsFromSingleIP.yaml

{
  "$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/83a0b48f-1cb7-4b4f-a018-23c3203a239b')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/83a0b48f-1cb7-4b4f-a018-23c3203a239b')]",
      "properties": {
        "alertRuleTemplateName": "83a0b48f-1cb7-4b4f-a018-23c3203a239b",
        "customDetails": null,
        "description": "'Detects requests with different user agents from one source in short timeframe.'\n",
        "displayName": "NGINX - Multiple user agents for single source",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IPCustomEntity",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/NGINX HTTP Server/Analytic Rules/NGINXDifferentUAsFromSingleIP.yaml",
        "query": "let threshold = 5;\nNGINXHTTPServer\n| summarize makeset(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 5m)\n| extend ua_count = array_length(set_HttpUserAgentOriginal)\n| where ua_count > threshold\n| extend IPCustomEntity = SrcIpAddr\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1133",
          "T1190"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}