GreyNoise TI map IP entity to OfficeActivity

id: c51628fe-999c-5150-9fd7-660fc4f58ed2
name: GreyNoise TI map IP entity to OfficeActivity
version: 1.0.1
kind: Scheduled
description: |
  This query maps any GreyNoise IP indicators of compromise (IOCs) from threat intelligence (TI), by searching for matches in OfficeActivity.
severity: Medium
requiredDataConnectors:
  - connectorId: ThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: Office365
    dataTypes:
      - OfficeActivity
  - connectorId: GreyNoise2SentinelAPI
    dataTypes:
      - ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1071
query: |
  let dt_lookBack = 1h; // Look back 1 hour for OfficeActivity events
  let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
  // Fetch threat intelligence indicators related to IP addresses
  let IP_Indicators = ThreatIntelligenceIndicator
    | where TimeGenerated >= ago(ioc_lookBack)
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where Active == true and ExpirationDateTime > now()
    | where SourceSystem == 'GreyNoise'
    | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
    | extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
    | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127.";
  // Perform a join between IP indicators and OfficeActivity events
  IP_Indicators
    // Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation
    | join kind=innerunique (
        OfficeActivity
        | where TimeGenerated >= ago(dt_lookBack)
        | where isnotempty(ClientIP)
        | extend ClientIPValues = extract_all(@'\[?(::ffff:)?(?P<IPAddress>(\d+\.\d+\.\d+\.\d+)|[^\]%]+)(%\d+)?\]?([-:](?P<Port>\d+))?', dynamic(["IPAddress", "Port"]), ClientIP)[0]
        | extend IPAddress = iff(array_length(ClientIPValues) > 0, tostring(ClientIPValues[0]), '')
        | extend OfficeActivity_TimeGenerated = TimeGenerated
    )
    on $left.TI_ipEntity == $right.IPAddress
    // Filter out OfficeActivity events that occurred after the expiration of the corresponding indicator
    | where OfficeActivity_TimeGenerated < ExpirationDateTime
    // Group the results by IndicatorId and keep the OfficeActivity event with the latest timestamp
    | summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId
    // Select the desired output fields
    | project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
      TI_ipEntity, ClientIP, UserId, Operation, ResultStatus, RecordType, OfficeObjectId, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
    | extend timestamp = OfficeActivity_TimeGenerated, Name = tostring(split(UserId, '@', 0)[0]), UPNSuffix = tostring(split(UserId, '@', 1)[0])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: TI_ipEntity
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url