Cloudflare - Multiple user agents for single source

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Id	fc50076a-0275-43d5-b9dd-38346c061f67
Rulename	Cloudflare - Multiple user agents for single source
Description	Detects requests with different user agents from one source in short timeframe.
Severity	Medium
Tactics	InitialAccess
Techniques	T1190 T1133
Required data connectors	CloudflareDataConnector
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cloudflare/Analytic Rules/CloudflareMultipleUAs.yaml
Version	1.0.0
Arm template	fc50076a-0275-43d5-b9dd-38346c061f67.json

KQL

let threshold = 10;
Cloudflare
| where isnotempty(HttpUserAgentOriginal)
| summarize d_ua = dcount(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 3m)
| where d_ua > threshold
| extend IPCustomEntity = SrcIpAddr

YAML

relevantTechniques:
- T1190
- T1133
name: Cloudflare - Multiple user agents for single source
requiredDataConnectors:
- dataTypes:
  - Cloudflare
  connectorId: CloudflareDataConnector
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: IPCustomEntity
  entityType: IP
triggerThreshold: 0
id: fc50076a-0275-43d5-b9dd-38346c061f67
tactics:
- InitialAccess
version: 1.0.0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cloudflare/Analytic Rules/CloudflareMultipleUAs.yaml
queryPeriod: 1h
kind: Scheduled
queryFrequency: 1h
severity: Medium
status: Available
description: |
    'Detects requests with different user agents from one source in short timeframe.'
query: |
  let threshold = 10;
  Cloudflare
  | where isnotempty(HttpUserAgentOriginal)
  | summarize d_ua = dcount(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 3m)
  | where d_ua > threshold
  | extend IPCustomEntity = SrcIpAddr  
triggerOperator: gt

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/fc50076a-0275-43d5-b9dd-38346c061f67')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/fc50076a-0275-43d5-b9dd-38346c061f67')]",
      "properties": {
        "alertRuleTemplateName": "fc50076a-0275-43d5-b9dd-38346c061f67",
        "customDetails": null,
        "description": "'Detects requests with different user agents from one source in short timeframe.'\n",
        "displayName": "Cloudflare - 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/Cloudflare/Analytic Rules/CloudflareMultipleUAs.yaml",
        "query": "let threshold = 10;\nCloudflare\n| where isnotempty(HttpUserAgentOriginal)\n| summarize d_ua = dcount(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 3m)\n| where d_ua > 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": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}