TI Map Domain entity to SecurityAlert

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let SecurityAlerts = SecurityAlert
| where TimeGenerated > ago(dt_lookBack)
| where AlertName != "TI map Domain entity to SecurityAlert"
| extend domain = todynamic(dynamic_to_json(extract_all(@"(((xn--)?[a-z0-9\-]+\.)+([a-z]+|(xn--[a-z0-9]+)))", dynamic([1]), tolower(Entities))))
| where isnotempty(domain)
| mv-expand domain
| extend domain = tostring(domain)
| extend EntitiesDynamicArray = parse_json(Entities)
| mv-apply EntitiesDynamicArray on
    (summarize
        HostName = take_anyif(tostring(EntitiesDynamicArray.HostName), EntitiesDynamicArray.Type == "host"),
        IP_addr = take_anyif(tostring(EntitiesDynamicArray.Address), EntitiesDynamicArray.Type == "ip")
    )
| extend Alert_TimeGenerated = TimeGenerated
| extend Alert_Description = Description;
let AlertDomains = SecurityAlerts
| distinct domain
| summarize make_list(domain);
let Domain_Indicators = materialize(ThreatIntelIndicators
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
| where IndicatorType == "domain-name"
| extend DomainName = tolower(ObservableValue)
| where TimeGenerated >= ago(ioc_lookBack)
| where DomainName in (AlertDomains)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil))
| extend Description = tostring(parse_json(Data).description)
| where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;");
Domain_Indicators
// Using innerunique to keep performance fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
| join kind=innerunique (SecurityAlerts) on $left.DomainName == $right.domain
| where Alert_TimeGenerated < ValidUntil
| summarize Alert_TimeGenerated = arg_max(Alert_TimeGenerated, *) by Id, AlertName
| extend ActivityGroupNames = extract("ActivityGroup:([^,]+)", 1, tostring(parse_json(Data).labels))
| extend Url = DomainName
| project Alert_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, ConfidenceScore, DomainName, AlertName, Alert_Description, ProviderName, AlertSeverity, ConfidenceLevel, HostName, IP_addr, Url, Entities, Type
| extend timestamp = Alert_TimeGenerated
| project-reorder *, ConfidenceScore, DomainName, AlertName, Alert_TimeGenerated, ProviderName, AlertSeverity, Entities, Type, timestamp

triggerThreshold: 0
triggerOperator: gt
kind: Scheduled
id: df88b403-1cb9-49ea-a43d-b6613051cf7f
queryPeriod: 14d
name: TI Map Domain entity to SecurityAlert
queryFrequency: 1h
severity: Medium
tactics:
- CommandAndControl
version: 1.4.7
description: |
  'Identifies a match in SecurityAlert table from any Domain IOC from TI'
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat%20Intelligence%20%28NEW%29/Analytic%20Rules/DomainEntity_SecurityAlert.yaml
entityMappings:
- entityType: Host
  fieldMappings:
  - columnName: HostName
    identifier: HostName
- entityType: IP
  fieldMappings:
  - columnName: IP_addr
    identifier: Address
- entityType: URL
  fieldMappings:
  - columnName: Url
    identifier: Url
relevantTechniques:
- T1071
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let SecurityAlerts = SecurityAlert
  | where TimeGenerated > ago(dt_lookBack)
  | where AlertName != "TI map Domain entity to SecurityAlert"
  | extend domain = todynamic(dynamic_to_json(extract_all(@"(((xn--)?[a-z0-9\-]+\.)+([a-z]+|(xn--[a-z0-9]+)))", dynamic([1]), tolower(Entities))))
  | where isnotempty(domain)
  | mv-expand domain
  | extend domain = tostring(domain)
  | extend EntitiesDynamicArray = parse_json(Entities)
  | mv-apply EntitiesDynamicArray on
      (summarize
          HostName = take_anyif(tostring(EntitiesDynamicArray.HostName), EntitiesDynamicArray.Type == "host"),
          IP_addr = take_anyif(tostring(EntitiesDynamicArray.Address), EntitiesDynamicArray.Type == "ip")
      )
  | extend Alert_TimeGenerated = TimeGenerated
  | extend Alert_Description = Description;
  let AlertDomains = SecurityAlerts
  | distinct domain
  | summarize make_list(domain);
  let Domain_Indicators = materialize(ThreatIntelIndicators
  | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
  | where IndicatorType == "domain-name"
  | extend DomainName = tolower(ObservableValue)
  | where TimeGenerated >= ago(ioc_lookBack)
  | where DomainName in (AlertDomains)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
  | where IsActive and (ValidUntil > now() or isempty(ValidUntil))
  | extend Description = tostring(parse_json(Data).description)
  | where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;");
  Domain_Indicators
  // Using innerunique to keep performance fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
  | join kind=innerunique (SecurityAlerts) on $left.DomainName == $right.domain
  | where Alert_TimeGenerated < ValidUntil
  | summarize Alert_TimeGenerated = arg_max(Alert_TimeGenerated, *) by Id, AlertName
  | extend ActivityGroupNames = extract("ActivityGroup:([^,]+)", 1, tostring(parse_json(Data).labels))
  | extend Url = DomainName
  | project Alert_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, ConfidenceScore, DomainName, AlertName, Alert_Description, ProviderName, AlertSeverity, ConfidenceLevel, HostName, IP_addr, Url, Entities, Type
  | extend timestamp = Alert_TimeGenerated
  | project-reorder *, ConfidenceScore, DomainName, AlertName, Alert_TimeGenerated, ProviderName, AlertSeverity, Entities, Type, timestamp
requiredDataConnectors:
- dataTypes:
  - ThreatIntelIndicators
  connectorId: ThreatIntelligence
- dataTypes:
  - ThreatIntelIndicators
  connectorId: ThreatIntelligenceTaxii
- dataTypes:
  - SecurityAlert
  connectorId: MicrosoftCloudAppSecurity
- dataTypes:
  - SecurityAlert
  connectorId: AzureSecurityCenter
- dataTypes:
  - ThreatIntelIndicators
  connectorId: MicrosoftDefenderThreatIntelligence

{
  "$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/df88b403-1cb9-49ea-a43d-b6613051cf7f')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/df88b403-1cb9-49ea-a43d-b6613051cf7f')]",
      "properties": {
        "alertRuleTemplateName": "df88b403-1cb9-49ea-a43d-b6613051cf7f",
        "customDetails": null,
        "description": "'Identifies a match in SecurityAlert table from any Domain IOC from TI'\n",
        "displayName": "TI Map Domain entity to SecurityAlert",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "HostName",
                "identifier": "HostName"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IP_addr",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Url",
                "identifier": "Url"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat%20Intelligence%20%28NEW%29/Analytic%20Rules/DomainEntity_SecurityAlert.yaml",
        "query": "let dt_lookBack = 1h;\nlet ioc_lookBack = 14d;\nlet SecurityAlerts = SecurityAlert\n| where TimeGenerated > ago(dt_lookBack)\n| where AlertName != \"TI map Domain entity to SecurityAlert\"\n| extend domain = todynamic(dynamic_to_json(extract_all(@\"(((xn--)?[a-z0-9\\-]+\\.)+([a-z]+|(xn--[a-z0-9]+)))\", dynamic([1]), tolower(Entities))))\n| where isnotempty(domain)\n| mv-expand domain\n| extend domain = tostring(domain)\n| extend EntitiesDynamicArray = parse_json(Entities)\n| mv-apply EntitiesDynamicArray on\n    (summarize\n        HostName = take_anyif(tostring(EntitiesDynamicArray.HostName), EntitiesDynamicArray.Type == \"host\"),\n        IP_addr = take_anyif(tostring(EntitiesDynamicArray.Address), EntitiesDynamicArray.Type == \"ip\")\n    )\n| extend Alert_TimeGenerated = TimeGenerated\n| extend Alert_Description = Description;\nlet AlertDomains = SecurityAlerts\n| distinct domain\n| summarize make_list(domain);\nlet Domain_Indicators = materialize(ThreatIntelIndicators\n| extend IndicatorType = replace(@\"\\[|\\]|\\\"\"\", \"\", tostring(split(ObservableKey, \":\", 0)))\n| where IndicatorType == \"domain-name\"\n| extend DomainName = tolower(ObservableValue)\n| where TimeGenerated >= ago(ioc_lookBack)\n| where DomainName in (AlertDomains)\n| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue\n| where IsActive and (ValidUntil > now() or isempty(ValidUntil))\n| extend Description = tostring(parse_json(Data).description)\n| where Description !contains_cs \"State: inactive;\" and Description !contains_cs \"State: falsepos;\");\nDomain_Indicators\n// Using innerunique to keep performance fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated\n| join kind=innerunique (SecurityAlerts) on $left.DomainName == $right.domain\n| where Alert_TimeGenerated < ValidUntil\n| summarize Alert_TimeGenerated = arg_max(Alert_TimeGenerated, *) by Id, AlertName\n| extend ActivityGroupNames = extract(\"ActivityGroup:([^,]+)\", 1, tostring(parse_json(Data).labels))\n| extend Url = DomainName\n| project Alert_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, ConfidenceScore, DomainName, AlertName, Alert_Description, ProviderName, AlertSeverity, ConfidenceLevel, HostName, IP_addr, Url, Entities, Type\n| extend timestamp = Alert_TimeGenerated\n| project-reorder *, ConfidenceScore, DomainName, AlertName, Alert_TimeGenerated, ProviderName, AlertSeverity, Entities, Type, timestamp\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "techniques": [
          "T1071"
        ],
        "templateVersion": "1.4.7",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}