TI map Email entity to PaloAlto CommonSecurityLog

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
ThreatIntelIndicators
//Filtering the table for Email related IOCs
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
| where isnotempty(IndicatorType) and IndicatorType == "email-addr"
| extend EmailSenderAddress = ObservableValue
| extend EmailSourceDomain = substring(EmailSenderAddress, indexof(EmailSenderAddress, "@") + 1, strlen(EmailSenderAddress) - indexof(EmailSenderAddress, "@") - 1)
| extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
| extend IndicatorId = tostring(split(Id, "--")[2])
| extend Url = iff(ObservableKey == "url:value", ObservableValue, "")
| where isnotempty(EmailSenderAddress)
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id
| where IsActive == true and ValidUntil > now()
| project-reorder *, TrafficLightProtocolLevel, EmailSenderAddress, EmailSourceDomain, Type
// 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 (
    CommonSecurityLog | where TimeGenerated >= ago(dt_lookBack) and isnotempty(DestinationUserID)
    // Filtering PAN Logs for specific event type to match relevant email entities
    | where DeviceVendor == "Palo Alto Networks" and  DeviceEventClassID == "wildfire" and ApplicationProtocol in ("smtp","pop3")
    | extend DestinationUserID = tolower(DestinationUserID)
    | where DestinationUserID matches regex emailregex
    | extend CommonSecurityLog_TimeGenerated = TimeGenerated
)
on $left.EmailSenderAddress == $right.DestinationUserID
| where CommonSecurityLog_TimeGenerated < ValidUntil
| extend Description = tostring(parse_json(Data).description)
| extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
| summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by Id, DestinationUserID
| project CommonSecurityLog_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, EmailSenderAddress, DestinationUserID, DeviceEventClassID, LogSeverity, DeviceAction, SourceIP, SourcePort,
DestinationIP, DestinationPort, Protocol, ApplicationProtocol, Url//,  EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType,
| extend timestamp = CommonSecurityLog_TimeGenerated

OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence (NEW)/Analytic Rules/EmailEntity_PaloAlto.yaml
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
  ThreatIntelIndicators
  //Filtering the table for Email related IOCs
  | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
  | where isnotempty(IndicatorType) and IndicatorType == "email-addr"
  | extend EmailSenderAddress = ObservableValue
  | extend EmailSourceDomain = substring(EmailSenderAddress, indexof(EmailSenderAddress, "@") + 1, strlen(EmailSenderAddress) - indexof(EmailSenderAddress, "@") - 1)
  | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
  | extend IndicatorId = tostring(split(Id, "--")[2])
  | extend Url = iff(ObservableKey == "url:value", ObservableValue, "")
  | where isnotempty(EmailSenderAddress)
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id
  | where IsActive == true and ValidUntil > now()
  | project-reorder *, TrafficLightProtocolLevel, EmailSenderAddress, EmailSourceDomain, Type
  // 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 (
      CommonSecurityLog | where TimeGenerated >= ago(dt_lookBack) and isnotempty(DestinationUserID)
      // Filtering PAN Logs for specific event type to match relevant email entities
      | where DeviceVendor == "Palo Alto Networks" and  DeviceEventClassID == "wildfire" and ApplicationProtocol in ("smtp","pop3")
      | extend DestinationUserID = tolower(DestinationUserID)
      | where DestinationUserID matches regex emailregex
      | extend CommonSecurityLog_TimeGenerated = TimeGenerated
  )
  on $left.EmailSenderAddress == $right.DestinationUserID
  | where CommonSecurityLog_TimeGenerated < ValidUntil
  | extend Description = tostring(parse_json(Data).description)
  | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
  | summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by Id, DestinationUserID
  | project CommonSecurityLog_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, EmailSenderAddress, DestinationUserID, DeviceEventClassID, LogSeverity, DeviceAction, SourceIP, SourcePort,
  DestinationIP, DestinationPort, Protocol, ApplicationProtocol, Url//,  EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType,
  | extend timestamp = CommonSecurityLog_TimeGenerated  
description: |
    'Identifies a match in CommonSecurityLog table from any Email IOC from TI'
severity: Medium
requiredDataConnectors:
- dataTypes:
  - CommonSecurityLog
  connectorId: PaloAltoNetworks
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: ThreatIntelligence
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: ThreatIntelligenceTaxii
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: MicrosoftDefenderThreatIntelligence
name: TI map Email entity to PaloAlto CommonSecurityLog
triggerThreshold: 0
tactics:
- InitialAccess
version: 1.2.7
relevantTechniques:
- T1566
triggerOperator: gt
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: DestinationUserID
    identifier: Name
- entityType: IP
  fieldMappings:
  - columnName: SourceIP
    identifier: Address
- entityType: URL
  fieldMappings:
  - columnName: Url
    identifier: Url
id: 17fe80fe-072f-44d4-b62c-97a5bce56a64
kind: Scheduled
queryFrequency: 1h
queryPeriod: 14d

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/17fe80fe-072f-44d4-b62c-97a5bce56a64')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/17fe80fe-072f-44d4-b62c-97a5bce56a64')]",
      "properties": {
        "alertRuleTemplateName": "17fe80fe-072f-44d4-b62c-97a5bce56a64",
        "customDetails": null,
        "description": "'Identifies a match in CommonSecurityLog table from any Email IOC from TI'\n",
        "displayName": "TI map Email entity to PaloAlto CommonSecurityLog",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "DestinationUserID",
                "identifier": "Name"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SourceIP",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Url",
                "identifier": "Url"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence (NEW)/Analytic Rules/EmailEntity_PaloAlto.yaml",
        "query": "let dt_lookBack = 1h;\nlet ioc_lookBack = 14d;\nlet emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\\.[a-zA-Z0-9-.]+$';\nThreatIntelIndicators\n//Filtering the table for Email related IOCs\n| extend IndicatorType = replace(@\"\\[|\\]|\\\"\"\", \"\", tostring(split(ObservableKey, \":\", 0)))\n| where isnotempty(IndicatorType) and IndicatorType == \"email-addr\"\n| extend EmailSenderAddress = ObservableValue\n| extend EmailSourceDomain = substring(EmailSenderAddress, indexof(EmailSenderAddress, \"@\") + 1, strlen(EmailSenderAddress) - indexof(EmailSenderAddress, \"@\") - 1)\n| extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)\n| extend IndicatorId = tostring(split(Id, \"--\")[2])\n| extend Url = iff(ObservableKey == \"url:value\", ObservableValue, \"\")\n| where isnotempty(EmailSenderAddress)\n| where TimeGenerated >= ago(ioc_lookBack)\n| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id\n| where IsActive == true and ValidUntil > now()\n| project-reorder *, TrafficLightProtocolLevel, EmailSenderAddress, EmailSourceDomain, Type\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    CommonSecurityLog | where TimeGenerated >= ago(dt_lookBack) and isnotempty(DestinationUserID)\n    // Filtering PAN Logs for specific event type to match relevant email entities\n    | where DeviceVendor == \"Palo Alto Networks\" and  DeviceEventClassID == \"wildfire\" and ApplicationProtocol in (\"smtp\",\"pop3\")\n    | extend DestinationUserID = tolower(DestinationUserID)\n    | where DestinationUserID matches regex emailregex\n    | extend CommonSecurityLog_TimeGenerated = TimeGenerated\n)\non $left.EmailSenderAddress == $right.DestinationUserID\n| where CommonSecurityLog_TimeGenerated < ValidUntil\n| extend Description = tostring(parse_json(Data).description)\n| extend ActivityGroupNames = extract(@\"ActivityGroup:(\\S+)\", 1, tostring(parse_json(Data).labels))\n| summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by Id, DestinationUserID\n| project CommonSecurityLog_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, EmailSenderAddress, DestinationUserID, DeviceEventClassID, LogSeverity, DeviceAction, SourceIP, SourcePort,\nDestinationIP, DestinationPort, Protocol, ApplicationProtocol, Url//,  EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType,\n| extend timestamp = CommonSecurityLog_TimeGenerated\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1566"
        ],
        "templateVersion": "1.2.7",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}