TI map IP entity to Web Session Events ASIM Web Session schema

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Id	e2559891-383c-4caf-ae67-55a008b9f89e
Rulename	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. This rule uses the Advanced Security Information Model (ASIM) and supports any web session source that complies with ASIM.
Severity	Medium
Tactics	Impact
Required data connectors	MicrosoftDefenderThreatIntelligence SquidProxy ThreatIntelligence ThreatIntelligenceTaxii Zscaler
Kind	Scheduled
Query frequency	1h
Query period	14d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/IPEntity_imWebSession.yaml
Version	1.2.4
Arm template	e2559891-383c-4caf-ae67-55a008b9f89e.json

KQL

let HAS_ANY_MAX = 10000;
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let IP_TI = ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  // 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."
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now();
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
| project imNWS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore,
  TI_ipEntity, Dvc, SrcIpAddr, DstIpAddr, Url, Type

YAML

requiredDataConnectors:
- connectorId: SquidProxy
  dataTypes:
  - SquidProxy_CL
- connectorId: Zscaler
  dataTypes:
  - CommonSecurityLog
- connectorId: ThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
- connectorId: ThreatIntelligenceTaxii
  dataTypes:
  - ThreatIntelligenceIndicator
- connectorId: MicrosoftDefenderThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
triggerOperator: gt
version: 1.2.4
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: DstIpAddr
  entityType: IP
customDetails:
  ThreatType: ThreatType
  IndicatorId: IndicatorId
  IoCExpirationTime: ExpirationDateTime
  EventTime: imNWS_TimeGenerated
  IoCConfidenceScore: ConfidenceScore
  IoCDescription: Description
  ActivityGroupNames: ActivityGroupNames
queryPeriod: 14d
alertDetailsOverride:
  alertDisplayNameFormat: The IP {{SrcIpAddr}} of the web request matches an IP IoC
  alertDescriptionFormat: The source address {{SrcIpAddr}} of the web request for the URL {{Url}} matches a known indicator of compromise of {{ThreatType}}. Consult the threat intelligence feed for more information about the indicator.
severity: Medium
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/IPEntity_imWebSession.yaml
tactics:
- Impact
kind: Scheduled
queryFrequency: 1h
description: |
    This rule identifies Web Sessions for which the source IP address is a known IoC. This rule uses the [Advanced Security Information Model (ASIM)](https://aka.ms/AboutASIM) and supports any web session source that complies with ASIM.
query: |
  let HAS_ANY_MAX = 10000;
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let IP_TI = ThreatIntelligenceIndicator
    | where TimeGenerated >= ago(ioc_lookBack)
    // 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."
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where Active == true and ExpirationDateTime > now();
  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
  | project imNWS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore,
    TI_ipEntity, Dvc, SrcIpAddr, DstIpAddr, Url, Type  
id: e2559891-383c-4caf-ae67-55a008b9f89e
triggerThreshold: 0
name: TI map IP entity to Web Session Events (ASIM Web Session schema)

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/e2559891-383c-4caf-ae67-55a008b9f89e')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/e2559891-383c-4caf-ae67-55a008b9f89e')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "The source address {{SrcIpAddr}} of the web request for the URL {{Url}} matches a known indicator of compromise of {{ThreatType}}. Consult the threat intelligence feed for more information about the indicator.",
          "alertDisplayNameFormat": "The IP {{SrcIpAddr}} of the web request matches an IP IoC"
        },
        "alertRuleTemplateName": "e2559891-383c-4caf-ae67-55a008b9f89e",
        "customDetails": {
          "ActivityGroupNames": "ActivityGroupNames",
          "EventTime": "imNWS_TimeGenerated",
          "IndicatorId": "IndicatorId",
          "IoCConfidenceScore": "ConfidenceScore",
          "IoCDescription": "Description",
          "IoCExpirationTime": "ExpirationDateTime",
          "ThreatType": "ThreatType"
        },
        "description": "This rule identifies Web Sessions for which the source IP address is a known IoC. This rule uses the [Advanced Security Information Model (ASIM)](https://aka.ms/AboutASIM) and supports any web session source that complies with ASIM.\n",
        "displayName": "TI map IP entity to Web Session Events (ASIM Web Session schema)",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "DstIpAddr",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/IPEntity_imWebSession.yaml",
        "query": "let HAS_ANY_MAX = 10000;\nlet dt_lookBack = 1h;\nlet ioc_lookBack = 14d;\nlet IP_TI = ThreatIntelligenceIndicator\n  | where TimeGenerated >= ago(ioc_lookBack)\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  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n  | where Active == true and ExpirationDateTime > now();\nlet IP_TI_list = toscalar(IP_TI\n  | 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  )\n  on $left.TI_ipEntity == $right.SrcIpAddr\n| where imNWS_TimeGenerated < ExpirationDateTime\n| summarize imNWS_TimeGenerated = arg_max(imNWS_TimeGenerated, *) by IndicatorId, DstIpAddr\n| project imNWS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore,\n  TI_ipEntity, Dvc, SrcIpAddr, DstIpAddr, Url, Type\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "templateVersion": "1.2.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}