ThreatConnect TI Map URL Entity to OfficeActivity Data

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
  ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where ExpirationDateTime > now() and Active == true
// Filter out non ThreatConnect TI Sources
| where SourceSystem startswith "ThreatConnect-"
// Picking up only IOC's that contain the entities we want
| where isnotempty(Url)
// using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
| join kind=innerunique (
  OfficeActivity
  | where TimeGenerated >= ago(dt_lookBack)
  //Extract the Url from a number of potential fields
  | extend Url = iif(OfficeWorkload == "AzureActiveDirectory",extract("(http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\\(\\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+);", 1,ModifiedProperties),tostring(parse_json(ModifiedProperties)[12].NewValue))
  | where isnotempty(Url)
  // Ensure we get a clean URL
  | extend Url = tostring(split(Url, ';')[0])
  | extend OfficeActivity_TimeGenerated = TimeGenerated
  // Project a single user identity that we can use for entity mapping
  | extend User = iif(isnotempty(UserId), UserId, iif(isnotempty(Actor), tostring(parse_json(Actor)[0].ID), tostring(parse_json(Parameters)[0].Value)))
) on Url
| where OfficeActivity_TimeGenerated < ExpirationDateTime
| summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, Url
| project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Operation,
UserType, OfficeWorkload, Parameters, Url, User
| extend timestamp = OfficeActivity_TimeGenerated, Name = tostring(split(User, '@', 0)[0]), UPNSuffix = tostring(split(User, '@', 1)[0])

relevantTechniques:
- T1071
name: ThreatConnect TI Map URL Entity to OfficeActivity Data
requiredDataConnectors:
- dataTypes:
  - OfficeActivity
  connectorId: Office365
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: ThreatIntelligence
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: MicrosoftDefenderThreatIntelligence
entityMappings:
- fieldMappings:
  - identifier: Name
    columnName: Name
  - identifier: UPNSuffix
    columnName: UPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: Url
    columnName: Url
  entityType: URL
triggerThreshold: 0
id: 12c3b31b-66a6-53ff-b6ab-6ae45e56dc92
tactics:
- CommandAndControl
version: 1.0.1
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/ThreatConnect/Analytic Rules/ThreatConnect_URLEntity_OfficeActivity.yaml
queryPeriod: 14d
kind: Scheduled
queryFrequency: 1h
severity: Medium
description: |
    'This query identifies any URL indicators of compromise (IOCs) from threat intelligence (TI) by searching for matches in OfficeActivity data.'
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
    ThreatIntelligenceIndicator
    | where TimeGenerated >= ago(ioc_lookBack)
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where ExpirationDateTime > now() and Active == true
  // Filter out non ThreatConnect TI Sources
  | where SourceSystem startswith "ThreatConnect-"
  // Picking up only IOC's that contain the entities we want
  | where isnotempty(Url)
  // using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
  | join kind=innerunique (
    OfficeActivity
    | where TimeGenerated >= ago(dt_lookBack)
    //Extract the Url from a number of potential fields
    | extend Url = iif(OfficeWorkload == "AzureActiveDirectory",extract("(http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\\(\\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+);", 1,ModifiedProperties),tostring(parse_json(ModifiedProperties)[12].NewValue))
    | where isnotempty(Url)
    // Ensure we get a clean URL
    | extend Url = tostring(split(Url, ';')[0])
    | extend OfficeActivity_TimeGenerated = TimeGenerated
    // Project a single user identity that we can use for entity mapping
    | extend User = iif(isnotempty(UserId), UserId, iif(isnotempty(Actor), tostring(parse_json(Actor)[0].ID), tostring(parse_json(Parameters)[0].Value)))
  ) on Url
  | where OfficeActivity_TimeGenerated < ExpirationDateTime
  | summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, Url
  | project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Operation,
  UserType, OfficeWorkload, Parameters, Url, User
  | extend timestamp = OfficeActivity_TimeGenerated, Name = tostring(split(User, '@', 0)[0]), UPNSuffix = tostring(split(User, '@', 1)[0])  
triggerOperator: gt

{
  "$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/12c3b31b-66a6-53ff-b6ab-6ae45e56dc92')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/12c3b31b-66a6-53ff-b6ab-6ae45e56dc92')]",
      "properties": {
        "alertRuleTemplateName": "12c3b31b-66a6-53ff-b6ab-6ae45e56dc92",
        "customDetails": null,
        "description": "'This query identifies any URL indicators of compromise (IOCs) from threat intelligence (TI) by searching for matches in OfficeActivity data.'\n",
        "displayName": "ThreatConnect TI Map URL Entity to OfficeActivity Data",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Url",
                "identifier": "Url"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/ThreatConnect/Analytic Rules/ThreatConnect_URLEntity_OfficeActivity.yaml",
        "query": "let dt_lookBack = 1h;\nlet ioc_lookBack = 14d;\n  ThreatIntelligenceIndicator\n  | where TimeGenerated >= ago(ioc_lookBack)\n  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n  | where ExpirationDateTime > now() and Active == true\n// Filter out non ThreatConnect TI Sources\n| where SourceSystem startswith \"ThreatConnect-\"\n// Picking up only IOC's that contain the entities we want\n| where isnotempty(Url)\n// using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated\n| join kind=innerunique (\n  OfficeActivity\n  | where TimeGenerated >= ago(dt_lookBack)\n  //Extract the Url from a number of potential fields\n  | extend Url = iif(OfficeWorkload == \"AzureActiveDirectory\",extract(\"(http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\\\\(\\\\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+);\", 1,ModifiedProperties),tostring(parse_json(ModifiedProperties)[12].NewValue))\n  | where isnotempty(Url)\n  // Ensure we get a clean URL\n  | extend Url = tostring(split(Url, ';')[0])\n  | extend OfficeActivity_TimeGenerated = TimeGenerated\n  // Project a single user identity that we can use for entity mapping\n  | extend User = iif(isnotempty(UserId), UserId, iif(isnotempty(Actor), tostring(parse_json(Actor)[0].ID), tostring(parse_json(Parameters)[0].Value)))\n) on Url\n| where OfficeActivity_TimeGenerated < ExpirationDateTime\n| summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, Url\n| project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Operation,\nUserType, OfficeWorkload, Parameters, Url, User\n| extend timestamp = OfficeActivity_TimeGenerated, Name = tostring(split(User, '@', 0)[0]), UPNSuffix = tostring(split(User, '@', 1)[0])\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "techniques": [
          "T1071"
        ],
        "templateVersion": "1.0.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}