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

id: 094a4e6e-1a0d-4d49-9d64-cfc3b01a0be1
name: TI map Domain entity to PaloAlto CommonSecurityLog
description: |
  Identifies a match in PaloAlto CommonSecurityLog table from any Domain 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
  let ioc_lookBack = 14d; // Look back 14 days
  // Create a list of top-level domains (TLDs) from the threat feed data for later validation
  let SecurityLog = materialize(
    CommonSecurityLog
      // Filter common security logs based on the specified time range
      | extend IngestionTime = ingestion_time()
      | where IngestionTime > ago(dt_lookBack)
      | where DeviceEventClassID =~ 'url'
      // Uncomment the line below to only alert on allowed connections
      //| where DeviceAction !~ "block-url"
      // Extract the domain from RequestURL, if not present, extract it from AdditionalExtensions
      | extend PA_Url = column_ifexists("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 !startswith "http://" and ApplicationProtocol !~ "ssl", strcat('http://', PA_Url), iif(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 CommonSecurityLog_TimeGenerated = TimeGenerated
  );
  let LogDomains = SecurityLog | distinct Domain | summarize make_list(Domain);
  // Retrieve threat intelligence indicators within the specified time range
  let Domain_Indicators = materialize(
      ThreatIntelIndicators
      | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
      | where isnotempty(IndicatorType) and IndicatorType == "domain-name"
      | extend DomainName = tolower(IndicatorType)
      | where isnotempty(DomainName)
      | where TimeGenerated >= ago(ioc_lookBack)
      | extend TI_DomainEntity = tolower(DomainName)
      //| where TI_DomainEntity in (LogDomains)
      | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id
      | where IsActive == true and ValidUntil > now());
  // Join threat intelligence indicators with common security logs
  Domain_Indicators | join kind=innerunique (SecurityLog) on $left.TI_DomainEntity == $right.Domain
  | where CommonSecurityLog_TimeGenerated < ValidUntil
  | summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by Id
  | extend Description = tostring(parse_json(Data).description), ActivityGroupNames = tostring(parse_json(Data).activitygroupnames)
  | project CommonSecurityLog_TimeGenerated, Description, ActivityGroupNames, PA_Url, Domain, Id, ValidUntil, Confidence, DeviceAction, DestinationIP, DestinationPort, DeviceName, SourceIP, SourcePort, ApplicationProtocol, RequestMethod, Type, TI_DomainEntity
  | 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