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

id: 418192ba-01b8-4be8-89b7-5b5396a9d062
name: TI map Domain entity to PaloAlto
description: |
  'Identifies a match in Palo Alto data in CommonSecurityLog table from any Domain IOC from TI'
severity: Medium
requiredDataConnectors:
  - connectorId: PaloAltoNetworks
    dataTypes:
      - CommonSecurityLog
  - 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;  // Duration to look back for recent logs (1 hour)
  let ioc_lookBack = 14d;  // Duration to look back for recent threat intelligence indicators (14 days)
  // Create a list of top-level domains (TLDs) in our threat feed for later validation of extracted domains
  let list_tlds = 
      ThreatIntelIndicators
      | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
      | where isnotempty(IndicatorType) and IndicatorType == "domain-name"
      | extend DomainName = tolower(ObservableValue)
      | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
      | where isnotempty(DomainName)
      | where TimeGenerated >= ago(ioc_lookBack)
      | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id
      | where IsActive == true and ValidUntil > now()
      | extend DomainName = tolower(DomainName)
      | extend parts = split(DomainName, '.')
      | extend tld = parts[(array_length(parts)-1)]
      | summarize count() by tostring(tld)
      | summarize make_list(tld);
  let Domain_Indicators = 
      ThreatIntelIndicators
      // Filter to pick up only IOC's that contain the entities we want (in this case, DomainName)
      | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
      | where isnotempty(IndicatorType) and IndicatorType == "domain-name"
      | extend DomainName = tolower(ObservableValue)
      | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
      | where isnotempty(DomainName)
      | where TimeGenerated >= ago(ioc_lookBack)
      | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id
      | where IsActive == true and ValidUntil > now()
      | extend TI_DomainEntity = DomainName
      | extend IndicatorId = tostring(split(Id, "--")[2]);
  Domain_Indicators
      | project-reorder *, IsActive, Tags, TrafficLightProtocolLevel, DomainName, Type, TI_DomainEntity
      // Join with CommonSecurityLog to find potential malicious activity
      | join kind=innerunique (
          CommonSecurityLog
          | extend IngestionTime = ingestion_time()
          | where IngestionTime > ago(dt_lookBack)
          | where DeviceVendor =~ 'Palo Alto Networks'
          | where DeviceEventClassID =~ 'url'
          // Uncomment the line below to only alert on allowed connections
          // | where DeviceAction !~ "block-url"
          // Extract domain from RequestURL, if not present, extract it from AdditionalExtensions
          | extend PA_Url = coalesce(RequestURL, "None")
          | extend PA_Url = iif(isempty(PA_Url) and AdditionalExtensions !startswith "PanOS", extract("([^\"]+)", 1, tolower(AdditionalExtensions)), trim('"', PA_Url))
          | extend PA_Url = iif(PA_Url !in~ ('None', 'http://None', 'https://None') and PA_Url !startswith "http://" and PA_Url !startswith "https://" and ApplicationProtocol !~ "ssl", strcat('http://', PA_Url), PA_Url)
          | extend PA_Url = iif(PA_Url !in~ ('None', 'http://None', 'https://None') and PA_Url !startswith "https://" and ApplicationProtocol =~ "ssl", strcat('https://', PA_Url), PA_Url)
          | extend Domain = trim(@"""", tostring(parse_url(PA_Url).Host))
          | where isnotempty(Domain)
          | extend Domain = tolower(Domain)
          | extend parts = split(Domain, '.')
          // Split out the top-level domain (TLD) for the purpose of checking if we have any TI indicators with this TLD to match on
          | extend tld = parts[(array_length(parts)-1)]
          // Validate parsed domain by checking TLD against TLDs from the threat feed and drop domains where there is no chance of a match
          | where tld in~ (list_tlds)
          | extend CommonSecurityLog_TimeGenerated = TimeGenerated
      ) on $left.TI_DomainEntity == $right.Domain
      | where CommonSecurityLog_TimeGenerated < ValidUntil
      // Group the results by IndicatorId and Domain and keep only the latest CommonSecurityLog_TimeGenerated
      | summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by IndicatorId, Domain
      // Select the desired fields for the final result set
      | extend Description = tostring(parse_json(Data).description)
      | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
      | project CommonSecurityLog_TimeGenerated, Description, ActivityGroupNames, PA_Url, Domain, IndicatorId, ValidUntil, Confidence, DeviceAction, DestinationIP, DestinationPort, DeviceName, SourceIP, SourcePort, ApplicationProtocol, RequestMethod, Type, TI_DomainEntity
      // Add a new field 'timestamp' for convenience, using the CommonSecurityLog_TimeGenerated as its value
      | extend timestamp = CommonSecurityLog_TimeGenerated
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: DeviceName
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIP
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: PA_Url
version: 1.4.2
kind: Scheduled