ThreatConnect TI Map URL Entity to OfficeActivity Data

id: 12c3b31b-66a6-53ff-b6ab-6ae45e56dc92
name: ThreatConnect TI Map URL Entity to OfficeActivity Data
version: 1.0.1
kind: Scheduled
description: |
  'This query identifies any URL indicators of compromise (IOCs) from threat intelligence (TI) by searching for matches in OfficeActivity data.'
severity: Medium
requiredDataConnectors:
  - connectorId: Office365
    dataTypes:
     - OfficeActivity
  - connectorId: ThreatIntelligence
    dataTypes:
     - ThreatIntelligenceIndicator
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1071
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])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url