Port scan detected ASIM Network Session schema

Back


Id	1da9853f-3dea-4ea9-b7e5-26730da3d537
Rulename	Port scan detected (ASIM Network Session schema)
Description	This rule identifies a possible port scan, in which a single source tries to access a large number of different ports is a short time frame. This may indicate that a port scanner is trying to identify open ports in order to penetrate a system. This analytic rule uses ASIM and supports any built-in or custom source that supports the ASIM NetworkSession schema
Severity	Medium
Tactics	Discovery
Techniques	T1046
Required data connectors	AIVectraStream AWSS3 AzureFirewall AzureMonitor(VMInsights) AzureNSG CheckPoint CiscoASA CiscoAsaAma CiscoMeraki Corelight Fortinet MicrosoftSysmonForLinux MicrosoftThreatProtection PaloAltoNetworks SecurityEvents WindowsForwardedEvents WindowsSecurityEvents Zscaler
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Network Session Essentials/Analytic Rules/PortScan.yaml
Version	1.0.6
Arm template	1da9853f-3dea-4ea9-b7e5-26730da3d537.json

KQL

let PortScanThreshold = 50;
_Im_NetworkSession
| where ipv4_is_private(SrcIpAddr) == False
| where SrcIpAddr !in ("127.0.0.1", "::1")
| summarize AttemptedPortsCount=dcount(DstPortNumber), AttemptedPorts=make_set(DstPortNumber, 100), ReportedBy=make_set(strcat(EventVendor, "/", EventProduct), 20) by SrcIpAddr, bin(TimeGenerated, 5m)
| where AttemptedPortsCount > PortScanThreshold

YAML

name: Port scan detected  (ASIM Network Session schema)
relevantTechniques:
- T1046
id: 1da9853f-3dea-4ea9-b7e5-26730da3d537
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Network Session Essentials/Analytic Rules/PortScan.yaml
requiredDataConnectors:
- dataTypes:
  - AWSVPCFlow
  connectorId: AWSS3
- dataTypes:
  - DeviceNetworkEvents
  connectorId: MicrosoftThreatProtection
- dataTypes:
  - SecurityEvent
  connectorId: SecurityEvents
- dataTypes:
  - SecurityEvent
  connectorId: WindowsSecurityEvents
- dataTypes:
  - WindowsEvent
  connectorId: WindowsForwardedEvents
- dataTypes:
  - CommonSecurityLog
  connectorId: Zscaler
- dataTypes:
  - Syslog
  connectorId: MicrosoftSysmonForLinux
- dataTypes:
  - CommonSecurityLog
  connectorId: PaloAltoNetworks
- dataTypes:
  - VMConnection
  connectorId: AzureMonitor(VMInsights)
- dataTypes:
  - AzureDiagnostics
  connectorId: AzureFirewall
- dataTypes:
  - AzureDiagnostics
  connectorId: AzureNSG
- dataTypes:
  - CommonSecurityLog
  connectorId: CiscoASA
- dataTypes:
  - CommonSecurityLog
  connectorId: CiscoAsaAma
- dataTypes:
  - Corelight_CL
  connectorId: Corelight
- dataTypes:
  - VectraStream
  connectorId: AIVectraStream
- dataTypes:
  - CommonSecurityLog
  connectorId: CheckPoint
- dataTypes:
  - CommonSecurityLog
  connectorId: Fortinet
- dataTypes:
  - Syslog
  - CiscoMerakiNativePoller
  connectorId: CiscoMeraki
version: 1.0.6
severity: Medium
triggerThreshold: 0
tags:
- ParentAlert: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Sophos%20XG%20Firewall/Analytic%20Rules/PortScanDetected.yaml
  version: 1.0.0
- SchemaVersion: 0.2.4
  Schema: ASimNetworkSessions
queryPeriod: 1h
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: SrcIpAddr
  entityType: IP
kind: Scheduled
alertDetailsOverride:
  alertDisplayNameFormat: Potential port scan from {{SrcIpAddr}}
  alertDescriptionFormat: A port scan has been performed from address {{SrcIpAddr}} over {{AttemptedPortsCount}} ports within 5 minutes. This may indicate that a [port scanner](https://en.wikipedia.org/wiki/Port_scanner) is trying to identify open ports in order to penetrate a system.
queryFrequency: 1h
status: Available
query: |
  let PortScanThreshold = 50;
  _Im_NetworkSession
  | where ipv4_is_private(SrcIpAddr) == False
  | where SrcIpAddr !in ("127.0.0.1", "::1")
  | summarize AttemptedPortsCount=dcount(DstPortNumber), AttemptedPorts=make_set(DstPortNumber, 100), ReportedBy=make_set(strcat(EventVendor, "/", EventProduct), 20) by SrcIpAddr, bin(TimeGenerated, 5m)
  | where AttemptedPortsCount > PortScanThreshold  
tactics:
- Discovery
customDetails:
  AttemptedPortsCount: AttemptedPortsCount
description: |
  'This rule identifies a possible port scan, in which a single source tries to access a large number of different ports is a short time frame. This may indicate that a [port scanner](https://en.wikipedia.org/wiki/Port_scanner) is trying to identify open ports in order to penetrate a system.
  This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM NetworkSession schema'  
triggerOperator: gt

ARM