TI map IP entity to AppServiceHTTPLogs

id: f9949656-473f-4503-bf43-a9d9890f7d08
name: TI map IP entity to AppServiceHTTPLogs
description: |
  Identifies a match in AppServiceHTTPLogs from any IP IOC from TI
severity: Medium
requiredDataConnectors:
  - connectorId: ThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1071
query: |
  let dt_lookBack = 1h; // Look back 1 hour for AppServiceHTTPLogs
  let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
  // Fetch threat intelligence indicators related to IP addresses
  let IP_Indicators = ThreatIntelligenceIndicator
    // Filter out indicators without relevant IP address fields
    | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
    | where TimeGenerated >= ago(ioc_lookBack)
    // Filtering out rows where the Confidence Score is less than 50 as they would not have an Alert Priority label. 
    | where ConfidenceScore > 50
    // Select the IP entity based on availability of different IP fields
    | 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)
    // Determine AlertPriority based on ConfidenceScore
    | extend AlertPriority = case(ConfidenceScore > 82, "High",
                                  ConfidenceScore > 74, "Medium",
                                  "Low")
    // Exclude local addresses using the ipv4_is_private operator and filtering out specific address prefixes
    | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127."
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where Active == true and ExpirationDateTime > now();
  // Perform a join between IP indicators and AppServiceHTTPLogs to identify potential malicious activity
  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 (
      AppServiceHTTPLogs | where TimeGenerated >= ago(dt_lookBack)
      | where isnotempty(CIp)
      | extend WebApp = split(_ResourceId, '/')[8]
      | extend AppService_TimeGenerated = TimeGenerated // Rename time column for clarity
    )
    on $left.TI_ipEntity == $right.CIp
    // Filter out logs that occurred after the expiration of the corresponding indicator
    | where AppService_TimeGenerated < ExpirationDateTime
    // Group the results by IndicatorId and CIp, and keep the log entry with the latest timestamp
    | summarize AppService_TimeGenerated = arg_max(AppService_TimeGenerated, *) by IndicatorId, CIp
    // Select the desired output fields
    | project AppService_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore, TI_ipEntity, CsUsername, WebApp = split(_ResourceId, '/')[8], CIp, CsHost, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, _ResourceId, Type, AlertPriority
    // Extract hostname and DNS domain from the CsHost field
    | extend HostName = tostring(split(CsHost, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(CsHost, '.'), 1, -1), '.'))
    // Rename the timestamp field
    | extend timestamp = AppService_TimeGenerated
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: DnsDomain   
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: CsUsername
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: CIp
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url
  - entityType: AzureResource
    fieldMappings:
      - identifier: ResourceId
        columnName: _ResourceId
alertDetailsOverride:
  alertSeverityColumnName: AlertPriority
version: 1.5.3
kind: Scheduled