Cloudflare - Multiple user agents for single source | Microsoft Sentinel Analytic Rules

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Id	fc50076a-0275-43d5-b9dd-38346c061f68
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%20CCF/Analytic%20Rules/CloudflareCCFMultipleUAs.yaml
Version	1.0.1
Arm template	fc50076a-0275-43d5-b9dd-38346c061f68.json

KQL

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

YAML

name: Cloudflare - Multiple user agents for single source
triggerOperator: gt
query: |
  let threshold = 10;
  Cloudflare
  | where isnotempty(HttpUserAgentOriginal)
  | summarize d_ua = dcount(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 3m)
  | where d_ua > threshold
queryFrequency: 1h
description: |
  'Detects requests with different user agents from one source in short timeframe.'
id: fc50076a-0275-43d5-b9dd-38346c061f68
triggerThreshold: 0
queryPeriod: 1h
version: 1.0.1
kind: Scheduled
status: Available
severity: Medium
requiredDataConnectors:
- connectorId: CloudflareDataConnector
  dataTypes:
  - Cloudflare
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cloudflare%20CCF/Analytic%20Rules/CloudflareCCFMultipleUAs.yaml
relevantTechniques:
- T1190
- T1133
tactics:
- InitialAccess
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: SrcIpAddr
  entityType: IP

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-38346c061f68')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/fc50076a-0275-43d5-b9dd-38346c061f68')]",
      "properties": {
        "alertRuleTemplateName": "fc50076a-0275-43d5-b9dd-38346c061f68",
        "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": "SrcIpAddr",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cloudflare%20CCF/Analytic%20Rules/CloudflareCCFMultipleUAs.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",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1133",
          "T1190"
        ],
        "templateVersion": "1.0.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}