GreyNoise TI map IP entity to Network Session Events ASIM Network Session schema

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let IP_TI = materialize (
ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| where SourceSystem == 'GreyNoise'
  | extend TI_ipEntity = coalesce(NetworkIP, NetworkDestinationIP, NetworkSourceIP,EmailSourceIpAddress,"NO_IP")
  | where TI_ipEntity != "NO_IP"
);
IP_TI
  // using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
| join kind=innerunique 
(
  _Im_NetworkSession (starttime=ago(dt_lookBack))
  | where isnotempty(SrcIpAddr)
  | summarize imNWS_mintime=min(TimeGenerated), imNWS_maxtime=max(TimeGenerated) by SrcIpAddr, DstIpAddr, Dvc, EventProduct, EventVendor  
  | lookup (IP_TI | project TI_ipEntity, Active) on $left.SrcIpAddr == $right.TI_ipEntity
  | project-rename SrcMatch = Active
  | lookup (IP_TI | project TI_ipEntity, Active) on $left.DstIpAddr == $right.TI_ipEntity
  | project-rename DstMatch = Active
  | where SrcMatch or DstMatch
  | extend 
      IoCIP = iff(SrcMatch, SrcIpAddr, DstIpAddr),
      IoCDirection = iff(SrcMatch, "Source", "Destination")
)on $left.TI_ipEntity == $right.IoCIP
| where imNWS_mintime < ExpirationDateTime
| project imNWS_mintime, imNWS_maxtime, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, SrcIpAddr, DstIpAddr, IoCDirection, IoCIP, Dvc, EventVendor, EventProduct

description: |
  'This rule identifies a match Network Sessions for which the source or destination IP address is a known GreyNoise IoC.
  This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM NetworkSession schema'  
triggerThreshold: 0
kind: Scheduled
alertDetailsOverride:
  alertDescriptionFormat: The {{IoCDirection}} address {{IoCIP}} of a network session  matched a known indicator of compromise of {{ThreatType}}. Consult the threat intelligence blead for more information on the indicator.
  alertDisplayNameFormat: A network session {{IoCDirection}} address {{IoCIP}} matched an IoC.
entityMappings:
- entityType: IP
  fieldMappings:
  - columnName: IoCIP
    identifier: Address
requiredDataConnectors:
- connectorId: AWSS3
  dataTypes:
  - AWSVPCFlow
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceNetworkEvents
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: WindowsSecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: WindowsForwardedEvents
  dataTypes:
  - WindowsEvent
- connectorId: Zscaler
  dataTypes:
  - CommonSecurityLog
- connectorId: MicrosoftSysmonForLinux
  dataTypes:
  - Syslog
- connectorId: PaloAltoNetworks
  dataTypes:
  - CommonSecurityLog
- connectorId: AzureMonitor(VMInsights)
  dataTypes:
  - VMConnection
- connectorId: AzureFirewall
  dataTypes:
  - AzureDiagnostics
- connectorId: AzureNSG
  dataTypes:
  - AzureDiagnostics
- connectorId: CiscoASA
  dataTypes:
  - CommonSecurityLog
- connectorId: CiscoAsaAma
  dataTypes:
  - CommonSecurityLog
- connectorId: Corelight
  dataTypes:
  - Corelight_CL
- connectorId: AIVectraStream
  dataTypes:
  - VectraStream
- connectorId: CheckPoint
  dataTypes:
  - CommonSecurityLog
- connectorId: Fortinet
  dataTypes:
  - CommonSecurityLog
- connectorId: MicrosoftDefenderThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
- connectorId: CiscoMeraki
  dataTypes:
  - Syslog
  - CiscoMerakiNativePoller
- connectorId: GreyNoise2SentinelAPI
  dataTypes:
  - ThreatIntelligenceIndicator
status: Available
customDetails:
  IoCIPDirection: IoCDirection
  EventStartTime: imNWS_mintime
  ActivityGroupNames: ActivityGroupNames
  IoCExpirationTime: ExpirationDateTime
  EventEndTime: imNWS_maxtime
  ThreatType: ThreatType
  IoCConfidenceScore: ConfidenceScore
  IoCDescription: Description
  IndicatorId: IndicatorId
triggerOperator: gt
tactics:
- CommandAndControl
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/GreyNoiseThreatIntelligence/Analytic Rules/GreyNoise_IPEntity_imNetworkSession.yaml
queryPeriod: 14d
id: 536e8e5c-ce0e-575e-bcc9-aba8e7bf9316
relevantTechniques:
- T1071
severity: Medium
name: GreyNoise TI map IP entity to Network Session Events (ASIM Network Session schema)
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let IP_TI = materialize (
  ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now()
  | where SourceSystem == 'GreyNoise'
    | extend TI_ipEntity = coalesce(NetworkIP, NetworkDestinationIP, NetworkSourceIP,EmailSourceIpAddress,"NO_IP")
    | where TI_ipEntity != "NO_IP"
  );
  IP_TI
    // using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
  | join kind=innerunique 
  (
    _Im_NetworkSession (starttime=ago(dt_lookBack))
    | where isnotempty(SrcIpAddr)
    | summarize imNWS_mintime=min(TimeGenerated), imNWS_maxtime=max(TimeGenerated) by SrcIpAddr, DstIpAddr, Dvc, EventProduct, EventVendor  
    | lookup (IP_TI | project TI_ipEntity, Active) on $left.SrcIpAddr == $right.TI_ipEntity
    | project-rename SrcMatch = Active
    | lookup (IP_TI | project TI_ipEntity, Active) on $left.DstIpAddr == $right.TI_ipEntity
    | project-rename DstMatch = Active
    | where SrcMatch or DstMatch
    | extend 
        IoCIP = iff(SrcMatch, SrcIpAddr, DstIpAddr),
        IoCDirection = iff(SrcMatch, "Source", "Destination")
  )on $left.TI_ipEntity == $right.IoCIP
  | where imNWS_mintime < ExpirationDateTime
  | project imNWS_mintime, imNWS_maxtime, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, SrcIpAddr, DstIpAddr, IoCDirection, IoCIP, Dvc, EventVendor, EventProduct  
queryFrequency: 1h
tags:
- Schema: ASIMNetworkSession
  SchemaVersion: 0.2.4
version: 1.0.3