CTE - Device Repeatedly Blocked Across Multiple Days

CybereinforceCTE_CL
| where EventType == "block.url"
| extend d = parse_json(Details)
| extend
    DeviceId = tostring(d.deviceId),
    HostName = iff(isnotempty(tostring(d.hostname)), tostring(d.hostname), strcat("cte-device-", substring(EntityId, 0, 8))),
    DeviceUser = tostring(d.deviceUser),
    DeviceOs = tostring(d.deviceOs),
    DeviceVersion = tostring(d.deviceVersion),
    RuleId = tostring(d.ruleId),
    RuleName = iff(isnotempty(tostring(d.ruleName)), tostring(d.ruleName), "Pattern Match"),
    Pattern = tostring(d.pattern),
    Url = tostring(d.url),
    Action = tostring(d.action),
    IsIoc = tobool(d.ioc),
    ClientIp = tostring(split(tostring(d.clientIp), ":")[0]),
    ClientPort = tostring(split(tostring(d.clientIp), ":")[1]),
    UserAgent = tostring(d.userAgent)
| summarize BlockDays=dcount(startofday(TimeGenerated)), BlockCount=count(), SampleUrls=make_set(Url, 20) by DeviceId, HostName, DeviceUser, DeviceOs, TenantId
| where BlockDays >= 3

name: CTE - Device Repeatedly Blocked Across Multiple Days
triggerOperator: gt
query: |
  CybereinforceCTE_CL
  | where EventType == "block.url"
  | extend d = parse_json(Details)
  | extend
      DeviceId = tostring(d.deviceId),
      HostName = iff(isnotempty(tostring(d.hostname)), tostring(d.hostname), strcat("cte-device-", substring(EntityId, 0, 8))),
      DeviceUser = tostring(d.deviceUser),
      DeviceOs = tostring(d.deviceOs),
      DeviceVersion = tostring(d.deviceVersion),
      RuleId = tostring(d.ruleId),
      RuleName = iff(isnotempty(tostring(d.ruleName)), tostring(d.ruleName), "Pattern Match"),
      Pattern = tostring(d.pattern),
      Url = tostring(d.url),
      Action = tostring(d.action),
      IsIoc = tobool(d.ioc),
      ClientIp = tostring(split(tostring(d.clientIp), ":")[0]),
      ClientPort = tostring(split(tostring(d.clientIp), ":")[1]),
      UserAgent = tostring(d.userAgent)
  | summarize BlockDays=dcount(startofday(TimeGenerated)), BlockCount=count(), SampleUrls=make_set(Url, 20) by DeviceId, HostName, DeviceUser, DeviceOs, TenantId
  | where BlockDays >= 3
queryFrequency: 12h
description: |
  A device has triggered URL blocks on 3 or more distinct days in the past week, suggesting a recurring risky browsing pattern or persistent exposure.
id: 8fbb095d-3a35-483b-b264-25b858a52f4d
triggerThreshold: 0
queryPeriod: 7d
version: 1.0.0
kind: Scheduled
relevantTechniques:
- T1189
severity: Medium
requiredDataConnectors:
- connectorId: cybereinforce_cte
  dataTypes:
  - CybereinforceCTE_CL
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cybereinforce/Analytic%20Rules/DeviceRepeatedlyBlockedAcrossMultipleDays.yaml
tactics:
- InitialAccess
entityMappings:
- fieldMappings:
  - identifier: HostName
    columnName: HostName
  entityType: Host

{
  "$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/8fbb095d-3a35-483b-b264-25b858a52f4d')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/8fbb095d-3a35-483b-b264-25b858a52f4d')]",
      "properties": {
        "alertRuleTemplateName": "8fbb095d-3a35-483b-b264-25b858a52f4d",
        "customDetails": null,
        "description": "A device has triggered URL blocks on 3 or more distinct days in the past week, suggesting a recurring risky browsing pattern or persistent exposure.\n",
        "displayName": "CTE - Device Repeatedly Blocked Across Multiple Days",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "HostName",
                "identifier": "HostName"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cybereinforce/Analytic%20Rules/DeviceRepeatedlyBlockedAcrossMultipleDays.yaml",
        "query": "CybereinforceCTE_CL\n| where EventType == \"block.url\"\n| extend d = parse_json(Details)\n| extend\n    DeviceId = tostring(d.deviceId),\n    HostName = iff(isnotempty(tostring(d.hostname)), tostring(d.hostname), strcat(\"cte-device-\", substring(EntityId, 0, 8))),\n    DeviceUser = tostring(d.deviceUser),\n    DeviceOs = tostring(d.deviceOs),\n    DeviceVersion = tostring(d.deviceVersion),\n    RuleId = tostring(d.ruleId),\n    RuleName = iff(isnotempty(tostring(d.ruleName)), tostring(d.ruleName), \"Pattern Match\"),\n    Pattern = tostring(d.pattern),\n    Url = tostring(d.url),\n    Action = tostring(d.action),\n    IsIoc = tobool(d.ioc),\n    ClientIp = tostring(split(tostring(d.clientIp), \":\")[0]),\n    ClientPort = tostring(split(tostring(d.clientIp), \":\")[1]),\n    UserAgent = tostring(d.userAgent)\n| summarize BlockDays=dcount(startofday(TimeGenerated)), BlockCount=count(), SampleUrls=make_set(Url, 20) by DeviceId, HostName, DeviceUser, DeviceOs, TenantId\n| where BlockDays >= 3\n",
        "queryFrequency": "PT12H",
        "queryPeriod": "P7D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1189"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}