(Preview) TI map IP entity to Web Session Events (ASIM Web Session schema)

let HAS_ANY_MAX = 10000;
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let IoCList = materialize(externaldata(TimeGenerated:datetime,IoC:string,IoC_Type:string,ExpirationDateTime:datetime,Description:string,Action:string, ConfidenceScore:real, ThreatType:string, Active:string,Type:string, TrafficLightProtocolLevel:string, ActivityGroupNames:string)[@"https://raw.githubusercontent.com/microsoft/mstic/master/RapidReleaseTI/Indicators.csv"] with(format="csv", ignoreFirstRecord=True));
let IP_TI= (union isfuzzy=true
(ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack) and ExpirationDateTime > now()
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true
// As there is potentially more than 1 indicator type for matching IP, taking NetworkIP first, then others if that is empty.
// Taking the first non-empty value based on potential IOC match availability
| extend TI_ipEntity = coalesce(NetworkIP, NetworkDestinationIP, NetworkSourceIP,EmailSourceIpAddress,"NO_IP")
// Picking up only IOC's that contain the entities we want
| where TI_ipEntity != "NO_IP"
//Exclude local addresses, using the ipv4_is_private operator
| where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127."
),
(IoCList
| where IoC_Type =~ 'IP'
| where ExpirationDateTime > now()
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IoC
| where Active =~ 'True'
| extend TI_ipEntity = IoC
| project-away  IoC_Type
)
);
let IP_TI_list=toscalar(IP_TI | summarize NIoCs= dcount(TI_ipEntity), IoCs=make_set(TI_ipEntity) 
  | project IoCs=iff(NIoCs > HAS_ANY_MAX, dynamic([]), IoCs )  );
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_WebSession (starttime=ago(dt_lookBack), srcipaddr_has_any_prefix=IP_TI_list)
    | where isnotempty(SrcIpAddr)
    // renaming time column so it is clear the log this came from
    | extend imNWS_TimeGenerated = TimeGenerated
)
on $left.TI_ipEntity == $right.SrcIpAddr
| where imNWS_TimeGenerated < ExpirationDateTime
| summarize imNWS_TimeGenerated = arg_max(imNWS_TimeGenerated , *) by IndicatorId, DstIpAddr, IoC
| project imNWS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore,
TI_ipEntity, Dvc, SrcIpAddr, DstIpAddr, Type

version: 1.1.0
queryFrequency: 1h
requiredDataConnectors:
- connectorId: SquidProxy
  dataTypes:
  - SquidProxy_CL
- connectorId: Zscaler
  dataTypes:
  - CommonSecurityLog
- connectorId: ThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
- connectorId: ThreatIntelligenceTaxii
  dataTypes:
  - ThreatIntelligenceIndicator
entityMappings:
- fieldMappings:
  - columnName: DstIpAddr
    identifier: Address
  entityType: IP
kind: Scheduled
queryPeriod: 14d
severity: Medium
query: |
  let HAS_ANY_MAX = 10000;
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let IoCList = materialize(externaldata(TimeGenerated:datetime,IoC:string,IoC_Type:string,ExpirationDateTime:datetime,Description:string,Action:string, ConfidenceScore:real, ThreatType:string, Active:string,Type:string, TrafficLightProtocolLevel:string, ActivityGroupNames:string)[@"https://raw.githubusercontent.com/microsoft/mstic/master/RapidReleaseTI/Indicators.csv"] with(format="csv", ignoreFirstRecord=True));
  let IP_TI= (union isfuzzy=true
  (ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack) and ExpirationDateTime > now()
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true
  // As there is potentially more than 1 indicator type for matching IP, taking NetworkIP first, then others if that is empty.
  // Taking the first non-empty value based on potential IOC match availability
  | extend TI_ipEntity = coalesce(NetworkIP, NetworkDestinationIP, NetworkSourceIP,EmailSourceIpAddress,"NO_IP")
  // Picking up only IOC's that contain the entities we want
  | where TI_ipEntity != "NO_IP"
  //Exclude local addresses, using the ipv4_is_private operator
  | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127."
  ),
  (IoCList
  | where IoC_Type =~ 'IP'
  | where ExpirationDateTime > now()
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IoC
  | where Active =~ 'True'
  | extend TI_ipEntity = IoC
  | project-away  IoC_Type
  )
  );
  let IP_TI_list=toscalar(IP_TI | summarize NIoCs= dcount(TI_ipEntity), IoCs=make_set(TI_ipEntity) 
    | project IoCs=iff(NIoCs > HAS_ANY_MAX, dynamic([]), IoCs )  );
  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_WebSession (starttime=ago(dt_lookBack), srcipaddr_has_any_prefix=IP_TI_list)
      | where isnotempty(SrcIpAddr)
      // renaming time column so it is clear the log this came from
      | extend imNWS_TimeGenerated = TimeGenerated
  )
  on $left.TI_ipEntity == $right.SrcIpAddr
  | where imNWS_TimeGenerated < ExpirationDateTime
  | summarize imNWS_TimeGenerated = arg_max(imNWS_TimeGenerated , *) by IndicatorId, DstIpAddr, IoC
  | project imNWS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore,
  TI_ipEntity, Dvc, SrcIpAddr, DstIpAddr, Type  
triggerOperator: gt
id: e2559891-383c-4caf-ae67-55a008b9f89e
description: |
    'This rule identifies Web Sessions for which the source IP address is a known IoC. <br><br>This rule uses the [Advanced Security Information Model (ASIM)](https://aka.ms/AboutASIM) and supports any web session source that complies with ASIM.'
triggerThreshold: 0
name: (Preview) TI map IP entity to Web Session Events (ASIM Web Session schema)
customDetails:
  ActivityGroupNames: ActivityGroupNames
  IoCExpirationTime: ExpirationDateTime
  IoCDescription: Description
  EventTime: imNWS_TimeGenerated
  IoCConfidenceScore: ConfidenceScore
  IndicatorId: IndicatorId
  ThreatType: ThreatType
tactics:
- Impact
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/IPEntity_imWebSession.yaml
alertDetailsOverride:
  alertDisplayNameFormat: The IP {{SrcIpAddr}} of a web request to hostname  {{domain}} matched an IoC
  alertDescriptionFormat: The source address {{SrcIpAddr}} of a web request for URL {{Url}} matched a known indicator of compromise of {{ThreatType}}. Consult the threat intelligence blead for more information on the indicator.

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/e2559891-383c-4caf-ae67-55a008b9f89e')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/e2559891-383c-4caf-ae67-55a008b9f89e')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "(Preview) TI map IP entity to Web Session Events (ASIM Web Session schema)",
        "description": "'This rule identifies Web Sessions for which the source IP address is a known IoC. <br><br>This rule uses the [Advanced Security Information Model (ASIM)](https://aka.ms/AboutASIM) and supports any web session source that complies with ASIM.'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let HAS_ANY_MAX = 10000;\nlet dt_lookBack = 1h;\nlet ioc_lookBack = 14d;\nlet IoCList = materialize(externaldata(TimeGenerated:datetime,IoC:string,IoC_Type:string,ExpirationDateTime:datetime,Description:string,Action:string, ConfidenceScore:real, ThreatType:string, Active:string,Type:string, TrafficLightProtocolLevel:string, ActivityGroupNames:string)[@\"https://raw.githubusercontent.com/microsoft/mstic/master/RapidReleaseTI/Indicators.csv\"] with(format=\"csv\", ignoreFirstRecord=True));\nlet IP_TI= (union isfuzzy=true\n(ThreatIntelligenceIndicator\n| where TimeGenerated >= ago(ioc_lookBack) and ExpirationDateTime > now()\n| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n| where Active == true\n// As there is potentially more than 1 indicator type for matching IP, taking NetworkIP first, then others if that is empty.\n// Taking the first non-empty value based on potential IOC match availability\n| extend TI_ipEntity = coalesce(NetworkIP, NetworkDestinationIP, NetworkSourceIP,EmailSourceIpAddress,\"NO_IP\")\n// Picking up only IOC's that contain the entities we want\n| where TI_ipEntity != \"NO_IP\"\n//Exclude local addresses, using the ipv4_is_private operator\n| where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith \"fe80\" and TI_ipEntity !startswith \"::\" and TI_ipEntity !startswith \"127.\"\n),\n(IoCList\n| where IoC_Type =~ 'IP'\n| where ExpirationDateTime > now()\n| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IoC\n| where Active =~ 'True'\n| extend TI_ipEntity = IoC\n| project-away  IoC_Type\n)\n);\nlet IP_TI_list=toscalar(IP_TI | summarize NIoCs= dcount(TI_ipEntity), IoCs=make_set(TI_ipEntity) \n  | project IoCs=iff(NIoCs > HAS_ANY_MAX, dynamic([]), IoCs )  );\nIP_TI\n// 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\n| join kind=innerunique (\n    _Im_WebSession (starttime=ago(dt_lookBack), srcipaddr_has_any_prefix=IP_TI_list)\n    | where isnotempty(SrcIpAddr)\n    // renaming time column so it is clear the log this came from\n    | extend imNWS_TimeGenerated = TimeGenerated\n)\non $left.TI_ipEntity == $right.SrcIpAddr\n| where imNWS_TimeGenerated < ExpirationDateTime\n| summarize imNWS_TimeGenerated = arg_max(imNWS_TimeGenerated , *) by IndicatorId, DstIpAddr, IoC\n| project imNWS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore,\nTI_ipEntity, Dvc, SrcIpAddr, DstIpAddr, Type\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "alertRuleTemplateName": "e2559891-383c-4caf-ae67-55a008b9f89e",
        "alertDetailsOverride": {
          "alertDescriptionFormat": "The source address {{SrcIpAddr}} of a web request for URL {{Url}} matched a known indicator of compromise of {{ThreatType}}. Consult the threat intelligence blead for more information on the indicator.",
          "alertDisplayNameFormat": "The IP {{SrcIpAddr}} of a web request to hostname  {{domain}} matched an IoC"
        },
        "customDetails": {
          "ActivityGroupNames": "ActivityGroupNames",
          "IoCExpirationTime": "ExpirationDateTime",
          "IndicatorId": "IndicatorId",
          "IoCDescription": "Description",
          "ThreatType": "ThreatType",
          "EventTime": "imNWS_TimeGenerated",
          "IoCConfidenceScore": "ConfidenceScore"
        },
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "identifier": "Address",
                "columnName": "DstIpAddr"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/IPEntity_imWebSession.yaml",
        "templateVersion": "1.1.0"
      }
    }
  ]
}