TI map IP entity to AzureNetworkAnalytics_CL (NSG Flow Logs)

id: 929160b7-4449-4307-a3f9-bb742d1b8f01
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:
      - ThreatIntelIndicators
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelIndicators
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelIndicators
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 = ThreatIntelIndicators
  //extract key part of kv pair
       | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
       | where IndicatorType in ("ipv4-addr", "ipv6-addr", "network-traffic")
       | extend NetworkSourceIP = toupper(ObservableValue)
       | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
    | where TimeGenerated >= ago(ioc_lookBack)
    | extend TI_ipEntity = iff(isnotempty(NetworkSourceIP), NetworkSourceIP, NetworkSourceIP)
    | 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 Id, ObservableValue
    | where IsActive and (ValidUntil > now() or isempty(ValidUntil));
  // Perform a join between IP indicators and AzureNetworkAnalytics_CL logs for NSG Flow information
  IP_Indicators
     | project-reorder *, Tags, TrafficLightProtocolLevel, NetworkSourceIP, Type, TI_ipEntity
    // 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 < ValidUntil
    // 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 Id, PIP
    // Select the desired output fields
    | extend Description = tostring(parse_json(Data).description)
    | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
    | project AzureNetworkAnalytics_CL_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence,
      TI_ipEntity, Computer, FlowDirection_s, FlowStatus_s, FlowType_s, SrcPublicIPs_s, DestPublicIPs_s, PublicIPs_s, L7Protocol_s, DestPort_d, NetworkSourceIP, 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: 1.4.6
kind: Scheduled