Microsoft Sentinel Analytic Rules
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NGINX - Multiple user agents for single source

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Id83a0b48f-1cb7-4b4f-a018-23c3203a239b
RulenameNGINX - Multiple user agents for single source
DescriptionDetects requests with different user agents from one source in short timeframe.
SeverityMedium
TacticsInitialAccess
TechniquesT1190
T1133
Required data connectorsCustomLogsAma
KindScheduled
Query frequency1h
Query period1h
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/NGINX HTTP Server/Analytic Rules/NGINXDifferentUAsFromSingleIP.yaml
Version1.0.2
Arm template83a0b48f-1cb7-4b4f-a018-23c3203a239b.json
Deploy To Azure
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
triggerThreshold: 0
requiredDataConnectors:
- connectorId: CustomLogsAma
  dataTypes:
  - NGINX_CL
severity: Medium
queryFrequency: 1h
id: 83a0b48f-1cb7-4b4f-a018-23c3203a239b
relevantTechniques:
- T1190
- T1133
queryPeriod: 1h
name: NGINX - Multiple user agents for single source
status: Available
kind: Scheduled
tactics:
- InitialAccess
triggerOperator: gt
version: 1.0.2
entityMappings:
- entityType: IP
  fieldMappings:
  - columnName: IPCustomEntity
    identifier: Address
description: |
    'Detects requests with different user agents from one source in short timeframe.'
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/NGINX HTTP Server/Analytic Rules/NGINXDifferentUAsFromSingleIP.yaml
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  
{
  "$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"
    }
  ]
}