Microsoft Sentinel Analytic Rules
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Cisco Umbrella - Empty User Agent Detected

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Id2b328487-162d-4034-b472-59f1d53684a1
RulenameCisco Umbrella - Empty User Agent Detected
DescriptionRule helps to detect empty and unusual user agent indicating web browsing activity by an unusual process other than a web browser.
SeverityMedium
TacticsCommandAndControl
Required data connectorsCiscoUmbrellaDataConnector
KindScheduled
Query frequency15m
Query period15m
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Detections/CiscoUmbrella/CiscoUmbrellaEmptyUserAgentDetected.yaml
Version1.1.2
Arm template2b328487-162d-4034-b472-59f1d53684a1.json
Deploy To Azure
let timeframe = 15m;
Cisco_Umbrella
| where EventType == "proxylogs"
| where TimeGenerated > ago(timeframe)
| where HttpUserAgentOriginal == ''
| extend Message = "Empty User Agent"
| project Message, SrcIpAddr, DstIpAddr, UrlOriginal, TimeGenerated
kind: Scheduled
triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/CiscoUmbrella/CiscoUmbrellaEmptyUserAgentDetected.yaml
requiredDataConnectors:
- dataTypes:
  - Cisco_Umbrella_proxy_CL
  connectorId: CiscoUmbrellaDataConnector
queryPeriod: 15m
tactics:
- CommandAndControl
severity: Medium
triggerOperator: gt
description: |
    'Rule helps to detect empty and unusual user agent indicating web browsing activity by an unusual process other than a web browser.'
query: |
  let timeframe = 15m;
  Cisco_Umbrella
  | where EventType == "proxylogs"
  | where TimeGenerated > ago(timeframe)
  | where HttpUserAgentOriginal == ''
  | extend Message = "Empty User Agent"
  | project Message, SrcIpAddr, DstIpAddr, UrlOriginal, TimeGenerated  
name: Cisco Umbrella - Empty User Agent Detected
version: 1.1.2
id: 2b328487-162d-4034-b472-59f1d53684a1
queryFrequency: 15m
entityMappings:
- entityType: URL
  fieldMappings:
  - columnName: UrlOriginal
    identifier: Url
- entityType: IP
  fieldMappings:
  - columnName: SrcIpAddr
    identifier: Address
{
  "$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/2b328487-162d-4034-b472-59f1d53684a1')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/2b328487-162d-4034-b472-59f1d53684a1')]",
      "properties": {
        "alertRuleTemplateName": "2b328487-162d-4034-b472-59f1d53684a1",
        "customDetails": null,
        "description": "'Rule helps to detect empty and unusual user agent indicating web browsing activity by an unusual process other than a web browser.'\n",
        "displayName": "Cisco Umbrella - Empty User Agent Detected",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "UrlOriginal",
                "identifier": "Url"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIpAddr",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/CiscoUmbrella/CiscoUmbrellaEmptyUserAgentDetected.yaml",
        "query": "let timeframe = 15m;\nCisco_Umbrella\n| where EventType == \"proxylogs\"\n| where TimeGenerated > ago(timeframe)\n| where HttpUserAgentOriginal == ''\n| extend Message = \"Empty User Agent\"\n| project Message, SrcIpAddr, DstIpAddr, UrlOriginal, TimeGenerated\n",
        "queryFrequency": "PT15M",
        "queryPeriod": "PT15M",
        "severity": "Medium",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "templateVersion": "1.1.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}