Port Scan

id: b2c5907b-1040-4692-9802-9946031017e8
name: Port Scan
description: |
  'Identifies a source IP scanning multiple open ports on Azure Firewall. This can indicate malicious scanning of ports by an attacker, trying to reveal open ports in the organization that can be compromised for initial access.

  Configurable Parameters:

  - Port scan time - the time range to look for multiple ports scanned. Default is set to 30 seconds.
  - Minimum different ports threshold - alert only if more than this number of ports scanned. Default is set to 100.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: AzureFirewall
    dataTypes:
      - AzureDiagnostics
      - AZFWApplicationRule
      - AZFWNetworkRule
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Discovery
  - Reconnaissance
relevantTechniques:
  - T1046
  - T1595.001
query: |
  let MinimumDifferentPortsThreshold = 100;
  let BinTime = 30s;
  // Exclude known benign scanner IPs in your environment to reduce noise
  let KnownScannerIPs = dynamic([]); 
  union isfuzzy=true(
  AZFWApplicationRule
  | where SourceIp !in (KnownScannerIPs)
  | summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn
  | where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold),
  (AZFWNetworkRule
  | where SourceIp !in (KnownScannerIPs)
  | extend Fqdn = DestinationIp
  | summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn
  | where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold),
  (AzureDiagnostics
  | where OperationName == "AzureFirewallApplicationRuleLog" or OperationName == "AzureFirewallNetworkRuleLog"
  | parse msg_s with * "from " SourceIp ":" SourcePort:int " to " Fqdn ":" DestinationPort:int *
  | where isnotempty(Fqdn) and isnotempty(SourceIp)
  | where SourceIp !in (KnownScannerIPs) 
  | summarize AlertTimedCountPortsInBinTime = dcount(DestinationPort) by SourceIp, bin(TimeGenerated, BinTime), Fqdn
  | where AlertTimedCountPortsInBinTime > MinimumDifferentPortsThreshold)
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIp
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Fqdn
alertDetailsOverride:
  alertDisplayNameFormat: 'Port Scan Detected from {{SourceIp}}'
  alertDescriptionFormat: 'Source IP {{SourceIp}} has scanned {{AlertTimedCountPortsInBinTime}} different ports within a short time frame, which may indicate reconnaissance activity.'
version: 1.1.3
kind: Scheduled