Solutions/Threat Intelligence (NEW)/Analytic Rules/IPEntity_AzureFirewall.yaml

id: 4992d2f3-d6c0-4271-adac-b23532ba4492
name: TI map IP entity to AzureFirewall
description: |
  Identifies a match in AzureFirewall (NetworkRule & ApplicationRule Logs) from any IP IOC from TI
severity: Medium
requiredDataConnectors:
  - connectorId: ThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: AzureFirewall
    dataTypes: 
      - AzureDiagnostics
  - 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 AzureDiagnostics 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 isnotempty(IndicatorType) and IndicatorType == "ipv4-addr"
       | extend NetworkSourceIP = toupper(ObservableValue)
       | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
    // Filter out indicators without relevant IP address fields
    | where isnotempty(NetworkSourceIP)
    | where TimeGenerated >= ago(ioc_lookBack)
    // Select the IP entity based on availability of different IP fields
    | extend TI_ipEntity = iff(isnotempty(NetworkSourceIP), NetworkSourceIP, NetworkSourceIP)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
    // 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 Id
    | where IsActive == true and ValidUntil > now();
  // Perform a join between IP indicators and AzureDiagnostics logs to identify potential malicious activity
  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 (
        AzureDiagnostics
        | where TimeGenerated >= ago(dt_lookBack)
        | where OperationName in ("AzureFirewallApplicationRuleLog", "AzureFirewallNetworkRuleLog")
        | parse kind=regex flags=U msg_s with Protocol 'request from ' SourceHost 'to ' DestinationHost @'\.? Action: ' Firewall_Action @'\.' Rest_msg
        | extend SourceAddress = extract(@'([\.0-9]+)(:[\.0-9]+)?', 1, SourceHost)
        | extend DestinationAddress = extract(@'([\.0-9]+)(:[\.0-9]+)?', 1, DestinationHost)
        | extend RemoteIP = case(not(ipv4_is_private(DestinationAddress)), DestinationAddress, not(ipv4_is_private(SourceAddress)), SourceAddress, "")
        | where isnotempty(RemoteIP) // Filter out traffic involving public addresses only
        | project-rename AzureFirewall_TimeGenerated = TimeGenerated
    )
    on $left.TI_ipEntity == $right.RemoteIP
    // Filter out logs that occurred after the expiration of the corresponding indicator
    | where AzureFirewall_TimeGenerated < ValidUntil
    // Group the results by IndicatorId and RemoteIP, and keep the log entry with the latest timestamp
    | summarize AzureFirewall_TimeGenerated = arg_max(AzureFirewall_TimeGenerated, *) by Id, RemoteIP
    // Select the desired output fields
    | extend Description = tostring(parse_json(Data).description)
    | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
    | project LatestIndicatorTime, Description, ActivityGroupNames, Id, ValidUntil, Confidence,
      AzureFirewall_TimeGenerated, TI_ipEntity, Resource, Category, msg_s, SourceAddress, DestinationAddress, Firewall_Action, Protocol,
      NetworkSourceIP, Type//, Url, NetworkIP, NetworkDestinationIP, DomainName, EmailSourceIpAddress
    // Rename the timestamp field
    | extend timestamp = AzureFirewall_TimeGenerated
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: TI_ipEntity
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url
version: 1.3.3
kind: Scheduled