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
queryPeriod: 1h
tactics:
- InitialAccess
requiredDataConnectors:
- dataTypes:
  - Cloudflare
  connectorId: CloudflareDataConnector
triggerThreshold: 0
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: IPCustomEntity
  entityType: IP
name: Cloudflare - Multiple user agents for single source
status: Available
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  
queryFrequency: 1h
id: fc50076a-0275-43d5-b9dd-38346c061f67
severity: Medium
description: |
    'Detects requests with different user agents from one source in short timeframe.'
version: 1.0.0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cloudflare/Analytic Rules/CloudflareMultipleUAs.yaml
kind: Scheduled
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": "2023-02-01-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",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1133",
          "T1190"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}