TI map IP entity to AzureNetworkAnalytics_CL (NSG Flow Logs)

id: a4025a76-6490-4e6b-bb69-d02be4b03f07
name: TI map IP entity to AzureNetworkAnalytics_CL (NSG Flow Logs)
description: |
  Identifies a match in AzureNetworkAnalytics_CL (NSG Flow Logs) from any IP IOC from TI that was Allowed
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 AzureNetworkAnalytics_CL logs
  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 isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
    | where TimeGenerated >= ago(ioc_lookBack)
    | 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."
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where Active == true and ExpirationDateTime > now();
  // Perform a join between IP indicators and AzureNetworkAnalytics_CL logs for NSG Flow information
  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 (
        AzureNetworkAnalytics_CL
        | where TimeGenerated >= ago(dt_lookBack)
        | extend AzureNetworkAnalytics_CL_TimeGenerated = TimeGenerated
        | extend PIPs = split(PublicIPs_s, '|', 0)
        | extend PIP = tostring(PIPs[0])
    )
    on $left.TI_ipEntity == $right.PIP
    // Filter out logs that occurred after the expiration of the corresponding indicator
    | where AzureNetworkAnalytics_CL_TimeGenerated < ExpirationDateTime
    // Filter out NSG Flow logs that are not allowed (FlowStatus_s == "A")
    | where FlowStatus_s == "A"
    // Group the results by IndicatorId and PIP (Public IP), and keep the log entry with the latest timestamp
    | summarize AzureNetworkAnalytics_CL_TimeGenerated = arg_max(AzureNetworkAnalytics_CL_TimeGenerated, *) by IndicatorId, PIP
    // Select the desired output fields
    | project AzureNetworkAnalytics_CL_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
      TI_ipEntity, Computer, FlowDirection_s, FlowStatus_s, FlowType_s, SrcPublicIPs_s, DestPublicIPs_s, PublicIPs_s, L7Protocol_s, DestPort_d, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
    // Extract hostname and DNS domain from the Computer field
    | extend HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))
    // Rename the timestamp field
    | extend timestamp = AzureNetworkAnalytics_CL_TimeGenerated
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Computer
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: DnsDomain
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: TI_ipEntity
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url
version: 1.4.3
kind: Scheduled