Microsoft Sentinel Analytic Rules
cloudbrothers.infoAzure Sentinel RepoToggle Dark/Light/Auto modeToggle Dark/Light/Auto modeToggle Dark/Light/Auto modeBack to homepage

TI map Email entity to SecurityAlert

Back
Id4b451ade-ed28-48e2-8fe7-60ae83ab2fa5
RulenameTI map Email entity to SecurityAlert
DescriptionIdentifies a match in SecurityAlert table from any Email IOC from TI which will extend coverage to datatypes such as MCAS, StorageThreatProtection and many others
SeverityMedium
TacticsInitialAccess
TechniquesT1566
Required data connectorsAzureSecurityCenter
MicrosoftDefenderThreatIntelligence
ThreatIntelligence
ThreatIntelligenceTaxii
KindScheduled
Query frequency1h
Query period14d
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence (NEW)/Analytic Rules/EmailEntity_SecurityAlert.yaml
Version1.2.11
Arm template4b451ade-ed28-48e2-8fe7-60ae83ab2fa5.json
Deploy To Azure
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 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 TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil))
  | 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 (
    SecurityAlert
    | where TimeGenerated >= ago(dt_lookBack)
    | extend MSTI = case(AlertName has "TI map" and VendorName == "Microsoft" and ProductName == 'Azure Sentinel', true, false)
    | where MSTI == false
    // Converting Entities into dynamic data type and use mv-expand to unpack the array
    | extend EntitiesDynamicArray = parse_json(Entities) | mv-expand EntitiesDynamicArray
    // Parsing relevant entity column to filter type account and creating new column by combining account and UPNSuffix
    | extend Entitytype = tostring(parse_json(EntitiesDynamicArray).Type), EntityName = tostring(parse_json(EntitiesDynamicArray).Name),
    EntityUPNSuffix = tostring(parse_json(EntitiesDynamicArray).UPNSuffix)
    | where Entitytype =~ "account"
    | extend EntityEmail = tolower(strcat(EntityName, "@", EntityUPNSuffix))
    | where EntityEmail matches regex emailregex
    | extend Alert_TimeGenerated = TimeGenerated
)
on $left.EmailSenderAddress == $right.EntityEmail
| where Alert_TimeGenerated < ValidUntil
| summarize Alert_TimeGenerated = arg_max(Alert_TimeGenerated, *) by Id, AlertName
| extend Description = tostring(parse_json(Data).description)
| extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
| project Alert_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence,
EmailSenderAddress, EntityEmail, AlertName, AlertType,
AlertSeverity, Entities, ProviderName, VendorName,Url//, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, 
| extend Name = tostring(split(EntityEmail, '@', 0)[0]), UPNSuffix = tostring(split(EntityEmail, '@', 1)[0])
| extend timestamp = Alert_TimeGenerated
entityMappings:
- fieldMappings:
  - columnName: EntityEmail
    identifier: FullName
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
  entityType: Account
- fieldMappings:
  - columnName: Url
    identifier: Url
  entityType: URL
triggerThreshold: 0
severity: Medium
queryFrequency: 1h
queryPeriod: 14d
relevantTechniques:
- T1566
triggerOperator: gt
id: 4b451ade-ed28-48e2-8fe7-60ae83ab2fa5
requiredDataConnectors:
- connectorId: AzureSecurityCenter
  dataTypes:
  - SecurityAlert
- connectorId: ThreatIntelligence
  dataTypes:
  - ThreatIntelIndicators
- connectorId: ThreatIntelligenceTaxii
  dataTypes:
  - ThreatIntelIndicators
- connectorId: MicrosoftDefenderThreatIntelligence
  dataTypes:
  - ThreatIntelIndicators
version: 1.2.11
name: TI map Email entity to SecurityAlert
description: |
    'Identifies a match in SecurityAlert table from any Email IOC from TI which will extend coverage to datatypes such as MCAS, StorageThreatProtection and many others'
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
  ThreatIntelIndicators
  //Filtering the table for Email related IOCs
  | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
  | where 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 TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
  | where IsActive and (ValidUntil > now() or isempty(ValidUntil))
    | 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 (
      SecurityAlert
      | where TimeGenerated >= ago(dt_lookBack)
      | extend MSTI = case(AlertName has "TI map" and VendorName == "Microsoft" and ProductName == 'Azure Sentinel', true, false)
      | where MSTI == false
      // Converting Entities into dynamic data type and use mv-expand to unpack the array
      | extend EntitiesDynamicArray = parse_json(Entities) | mv-expand EntitiesDynamicArray
      // Parsing relevant entity column to filter type account and creating new column by combining account and UPNSuffix
      | extend Entitytype = tostring(parse_json(EntitiesDynamicArray).Type), EntityName = tostring(parse_json(EntitiesDynamicArray).Name),
      EntityUPNSuffix = tostring(parse_json(EntitiesDynamicArray).UPNSuffix)
      | where Entitytype =~ "account"
      | extend EntityEmail = tolower(strcat(EntityName, "@", EntityUPNSuffix))
      | where EntityEmail matches regex emailregex
      | extend Alert_TimeGenerated = TimeGenerated
  )
  on $left.EmailSenderAddress == $right.EntityEmail
  | where Alert_TimeGenerated < ValidUntil
  | summarize Alert_TimeGenerated = arg_max(Alert_TimeGenerated, *) by Id, AlertName
  | extend Description = tostring(parse_json(Data).description)
  | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
  | project Alert_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence,
  EmailSenderAddress, EntityEmail, AlertName, AlertType,
  AlertSeverity, Entities, ProviderName, VendorName,Url//, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, 
  | extend Name = tostring(split(EntityEmail, '@', 0)[0]), UPNSuffix = tostring(split(EntityEmail, '@', 1)[0])
  | extend timestamp = Alert_TimeGenerated  
tactics:
- InitialAccess
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence (NEW)/Analytic Rules/EmailEntity_SecurityAlert.yaml
kind: Scheduled
{
  "$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/4b451ade-ed28-48e2-8fe7-60ae83ab2fa5')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/4b451ade-ed28-48e2-8fe7-60ae83ab2fa5')]",
      "properties": {
        "alertRuleTemplateName": "4b451ade-ed28-48e2-8fe7-60ae83ab2fa5",
        "customDetails": null,
        "description": "'Identifies a match in SecurityAlert table from any Email IOC from TI which will extend coverage to datatypes such as MCAS, StorageThreatProtection and many others'\n",
        "displayName": "TI map Email entity to SecurityAlert",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "EntityEmail",
                "identifier": "FullName"
              },
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Url",
                "identifier": "Url"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence (NEW)/Analytic Rules/EmailEntity_SecurityAlert.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 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 TimeGenerated >= ago(ioc_lookBack)\n| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue\n| where IsActive and (ValidUntil > now() or isempty(ValidUntil))\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    SecurityAlert\n    | where TimeGenerated >= ago(dt_lookBack)\n    | extend MSTI = case(AlertName has \"TI map\" and VendorName == \"Microsoft\" and ProductName == 'Azure Sentinel', true, false)\n    | where MSTI == false\n    // Converting Entities into dynamic data type and use mv-expand to unpack the array\n    | extend EntitiesDynamicArray = parse_json(Entities) | mv-expand EntitiesDynamicArray\n    // Parsing relevant entity column to filter type account and creating new column by combining account and UPNSuffix\n    | extend Entitytype = tostring(parse_json(EntitiesDynamicArray).Type), EntityName = tostring(parse_json(EntitiesDynamicArray).Name),\n    EntityUPNSuffix = tostring(parse_json(EntitiesDynamicArray).UPNSuffix)\n    | where Entitytype =~ \"account\"\n    | extend EntityEmail = tolower(strcat(EntityName, \"@\", EntityUPNSuffix))\n    | where EntityEmail matches regex emailregex\n    | extend Alert_TimeGenerated = TimeGenerated\n)\non $left.EmailSenderAddress == $right.EntityEmail\n| where Alert_TimeGenerated < ValidUntil\n| summarize Alert_TimeGenerated = arg_max(Alert_TimeGenerated, *) by Id, AlertName\n| extend Description = tostring(parse_json(Data).description)\n| extend ActivityGroupNames = extract(@\"ActivityGroup:(\\S+)\", 1, tostring(parse_json(Data).labels))\n| project Alert_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence,\nEmailSenderAddress, EntityEmail, AlertName, AlertType,\nAlertSeverity, Entities, ProviderName, VendorName,Url//, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, \n| extend Name = tostring(split(EntityEmail, '@', 0)[0]), UPNSuffix = tostring(split(EntityEmail, '@', 1)[0])\n| extend timestamp = Alert_TimeGenerated\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1566"
        ],
        "templateVersion": "1.2.11",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}