TI Map IP Entity to CommonSecurityLog

let IPRegex = '[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}';
let dt_lookBack = 1h; // Look back 1 hour for CommonSecurityLog events
let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
// Fetch threat intelligence indicators related to IP addresses
let IP_Indicators = ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now()
  | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
  | extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
  | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127.";
// Perform a join between IP indicators and CommonSecurityLog events
IP_Indicators
  // Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation
  | join kind=innerunique (
      CommonSecurityLog
      | where TimeGenerated >= ago(dt_lookBack)
      | extend MessageIP = extract(IPRegex, 0, Message)
      | extend CS_ipEntity = iff(isnotempty(SourceIP), SourceIP, DestinationIP)
      | extend CS_ipEntity = iff(isempty(CS_ipEntity) and isnotempty(MessageIP), MessageIP, CS_ipEntity)
      | extend CommonSecurityLog_TimeGenerated = TimeGenerated
  )
  on $left.TI_ipEntity == $right.CS_ipEntity
  // Filter out logs that occurred after the expiration of the corresponding indicator
  | where CommonSecurityLog_TimeGenerated < ExpirationDateTime
  // Group the results by IndicatorId and CS_ipEntity, and keep the log entry with the latest timestamp
  | summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by IndicatorId, CS_ipEntity
  // Select the desired output fields
  | project timestamp = CommonSecurityLog_TimeGenerated, SourceIP, DestinationIP, MessageIP, Message, DeviceVendor, DeviceProduct, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, TI_ipEntity, CS_ipEntity, LogSeverity, DeviceAction, Type

severity: Medium
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/IPEntity_CustomSecurityLog.yaml
description: |
    This query maps any IP indicators of compromise (IOCs) from threat intelligence (TI), by searching for matches in CommonSecurityLog.
triggerOperator: gt
queryPeriod: 14d
requiredDataConnectors:
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: ThreatIntelligence
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: ThreatIntelligenceTaxii
- dataTypes:
  - CommonSecurityLog
  connectorId: CEF
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: MicrosoftDefenderThreatIntelligence
queryFrequency: 1h
triggerThreshold: 0
tactics:
- Impact
query: |
  let IPRegex = '[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}';
  let dt_lookBack = 1h; // Look back 1 hour for CommonSecurityLog events
  let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
  // Fetch threat intelligence indicators related to IP addresses
  let IP_Indicators = ThreatIntelligenceIndicator
    | where TimeGenerated >= ago(ioc_lookBack)
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where Active == true and ExpirationDateTime > now()
    | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
    | extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
    | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127.";
  // Perform a join between IP indicators and CommonSecurityLog events
  IP_Indicators
    // Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation
    | join kind=innerunique (
        CommonSecurityLog
        | where TimeGenerated >= ago(dt_lookBack)
        | extend MessageIP = extract(IPRegex, 0, Message)
        | extend CS_ipEntity = iff(isnotempty(SourceIP), SourceIP, DestinationIP)
        | extend CS_ipEntity = iff(isempty(CS_ipEntity) and isnotempty(MessageIP), MessageIP, CS_ipEntity)
        | extend CommonSecurityLog_TimeGenerated = TimeGenerated
    )
    on $left.TI_ipEntity == $right.CS_ipEntity
    // Filter out logs that occurred after the expiration of the corresponding indicator
    | where CommonSecurityLog_TimeGenerated < ExpirationDateTime
    // Group the results by IndicatorId and CS_ipEntity, and keep the log entry with the latest timestamp
    | summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by IndicatorId, CS_ipEntity
    // Select the desired output fields
    | project timestamp = CommonSecurityLog_TimeGenerated, SourceIP, DestinationIP, MessageIP, Message, DeviceVendor, DeviceProduct, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, TI_ipEntity, CS_ipEntity, LogSeverity, DeviceAction, Type  
kind: Scheduled
version: 1.2.0
id: 66c81ae2-1f89-4433-be00-2fbbd9ba5ebe
entityMappings:
- fieldMappings:
  - columnName: CS_ipEntity
    identifier: Address
  entityType: IP
name: TI Map IP Entity to CommonSecurityLog

{
  "$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/66c81ae2-1f89-4433-be00-2fbbd9ba5ebe')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/66c81ae2-1f89-4433-be00-2fbbd9ba5ebe')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01-preview",
      "properties": {
        "displayName": "TI Map IP Entity to CommonSecurityLog",
        "description": "This query maps any IP indicators of compromise (IOCs) from threat intelligence (TI), by searching for matches in CommonSecurityLog.\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let IPRegex = '[0-9]{1,3}\\\\.[0-9]{1,3}\\\\.[0-9]{1,3}\\\\.[0-9]{1,3}';\nlet dt_lookBack = 1h; // Look back 1 hour for CommonSecurityLog events\nlet ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators\n// Fetch threat intelligence indicators related to IP addresses\nlet IP_Indicators = ThreatIntelligenceIndicator\n  | where TimeGenerated >= ago(ioc_lookBack)\n  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n  | where Active == true and ExpirationDateTime > now()\n  | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)\n  | extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)\n  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)\n  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)\n  | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith \"fe80\" and TI_ipEntity !startswith \"::\" and TI_ipEntity !startswith \"127.\";\n// Perform a join between IP indicators and CommonSecurityLog events\nIP_Indicators\n  // Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation\n  | join kind=innerunique (\n      CommonSecurityLog\n      | where TimeGenerated >= ago(dt_lookBack)\n      | extend MessageIP = extract(IPRegex, 0, Message)\n      | extend CS_ipEntity = iff(isnotempty(SourceIP), SourceIP, DestinationIP)\n      | extend CS_ipEntity = iff(isempty(CS_ipEntity) and isnotempty(MessageIP), MessageIP, CS_ipEntity)\n      | extend CommonSecurityLog_TimeGenerated = TimeGenerated\n  )\n  on $left.TI_ipEntity == $right.CS_ipEntity\n  // Filter out logs that occurred after the expiration of the corresponding indicator\n  | where CommonSecurityLog_TimeGenerated < ExpirationDateTime\n  // Group the results by IndicatorId and CS_ipEntity, and keep the log entry with the latest timestamp\n  | summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by IndicatorId, CS_ipEntity\n  // Select the desired output fields\n  | project timestamp = CommonSecurityLog_TimeGenerated, SourceIP, DestinationIP, MessageIP, Message, DeviceVendor, DeviceProduct, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, TI_ipEntity, CS_ipEntity, LogSeverity, DeviceAction, Type\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "alertRuleTemplateName": "66c81ae2-1f89-4433-be00-2fbbd9ba5ebe",
        "customDetails": null,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "CS_ipEntity",
                "identifier": "Address"
              }
            ]
          }
        ],
        "templateVersion": "1.2.0",
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/IPEntity_CustomSecurityLog.yaml"
      }
    }
  ]
}