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Red Sift - New email with URL from previously unseen sender

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Id6e0b70d4-0ab8-480e-9707-8ad45fc21a65
RulenameRed Sift - New email with URL from previously unseen sender
DescriptionDetects email forensics events that contain one or more URLs where the sender in the from field has not been seen in the previous 14 days, which may indicate phishing activity or a newly observed sender.
SeverityMedium
TacticsInitialAccess
TechniquesT1566
Required data connectorsRedSiftPush
KindScheduled
Query frequency1h
Query period14d
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Red%20Sift/Analytic%20Rules/RedSiftEmailUrlFromNewSender.yaml
Version1.0.0
Arm template6e0b70d4-0ab8-480e-9707-8ad45fc21a65.json
Deploy To Azure
let lookback = 14d;
let recentWindow = 1h;
let historicalSenders = RedSiftEmailForensics_CL
| extend
    EmailFrom = tostring(column_ifexists("EmailFrom", ""))
| where TimeGenerated between (ago(lookback) .. ago(recentWindow))
| where isnotempty(EmailFrom)
| summarize by EmailFrom;
RedSiftEmailForensics_CL
| extend
    EmailFrom = tostring(column_ifexists("EmailFrom", "")),
    EmailSubject = tostring(column_ifexists("EmailSubject", "")),
    EmailReturnPath = tostring(column_ifexists("EmailReturnPath", "")),
    EmailMessageUid = tostring(column_ifexists("EmailMessageUid", "")),
    SrcIp = tostring(column_ifexists("SrcIp", "")),
    DstHostname = tostring(column_ifexists("DstHostname", "")),
    Severity = tostring(column_ifexists("Severity", "")),
    Message = tostring(column_ifexists("Message", "")),
    CorrelationUid = tostring(column_ifexists("CorrelationUid", "")),
    EmailUrls = todynamic(column_ifexists("EmailUrls", "[]"))
| where TimeGenerated >= ago(recentWindow)
| where isnotempty(EmailFrom)
| extend UrlCount = array_length(EmailUrls)
| where UrlCount > 0
| mv-apply Url = EmailUrls on (
    summarize UrlSet = make_set(tostring(Url.url_string), 50)
  )
| extend UrlList = strcat_array(UrlSet, ", ")
| join kind=leftanti (historicalSenders) on EmailFrom
| project
    TimeGenerated,
    EmailFrom,
    EmailSubject,
    EmailReturnPath,
    EmailMessageUid,
    SrcIp,
    DstHostname,
    UrlCount,
    UrlList,
    Severity,
    Message,
    CorrelationUid

entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: EmailFrom
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SrcIp
- entityType: DNS
  fieldMappings:
  - identifier: DomainName
    columnName: DstHostname
name: Red Sift - New email with URL from previously unseen sender
kind: Scheduled
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Red%20Sift/Analytic%20Rules/RedSiftEmailUrlFromNewSender.yaml
triggerOperator: gt
status: Available
suppressionDuration: PT1H
queryPeriod: 14d
requiredDataConnectors:
- connectorId: RedSiftPush
  dataTypes:
  - RedSiftEmailForensics_CL
tactics:
- InitialAccess
query: |
  let lookback = 14d;
  let recentWindow = 1h;
  let historicalSenders = RedSiftEmailForensics_CL
  | extend
      EmailFrom = tostring(column_ifexists("EmailFrom", ""))
  | where TimeGenerated between (ago(lookback) .. ago(recentWindow))
  | where isnotempty(EmailFrom)
  | summarize by EmailFrom;
  RedSiftEmailForensics_CL
  | extend
      EmailFrom = tostring(column_ifexists("EmailFrom", "")),
      EmailSubject = tostring(column_ifexists("EmailSubject", "")),
      EmailReturnPath = tostring(column_ifexists("EmailReturnPath", "")),
      EmailMessageUid = tostring(column_ifexists("EmailMessageUid", "")),
      SrcIp = tostring(column_ifexists("SrcIp", "")),
      DstHostname = tostring(column_ifexists("DstHostname", "")),
      Severity = tostring(column_ifexists("Severity", "")),
      Message = tostring(column_ifexists("Message", "")),
      CorrelationUid = tostring(column_ifexists("CorrelationUid", "")),
      EmailUrls = todynamic(column_ifexists("EmailUrls", "[]"))
  | where TimeGenerated >= ago(recentWindow)
  | where isnotempty(EmailFrom)
  | extend UrlCount = array_length(EmailUrls)
  | where UrlCount > 0
  | mv-apply Url = EmailUrls on (
      summarize UrlSet = make_set(tostring(Url.url_string), 50)
    )
  | extend UrlList = strcat_array(UrlSet, ", ")
  | join kind=leftanti (historicalSenders) on EmailFrom
  | project
      TimeGenerated,
      EmailFrom,
      EmailSubject,
      EmailReturnPath,
      EmailMessageUid,
      SrcIp,
      DstHostname,
      UrlCount,
      UrlList,
      Severity,
      Message,
      CorrelationUid
description: |
  'Detects email forensics events that contain one or more URLs where the sender in the from field has not been seen in the previous 14 days, which may indicate phishing activity or a newly observed sender.'
severity: Medium
incidentConfiguration:
  groupingConfiguration:
    lookbackDuration: P1D
    groupByCustomDetails:
    - EmailSubject
    groupByEntities:
    - Account
    enabled: true
    matchingMethod: Selected
    reopenClosedIncident: false
  createIncident: true
id: 6e0b70d4-0ab8-480e-9707-8ad45fc21a65
customDetails:
  ReturnPath: EmailReturnPath
  UrlList: UrlList
  CorrelationUid: CorrelationUid
  EmailSubject: EmailSubject
  UrlCount: UrlCount
suppressionEnabled: false
triggerThreshold: 0
queryFrequency: 1h
eventGroupingSettings:
  aggregationKind: AlertPerResult
alertDetailsOverride:
  alertDescriptionFormat: Email from previously unseen sender {{EmailFrom}} contains {{UrlCount}} URL(s).
  alertDisplayNameFormat: RedSift - New URL-bearing sender {{EmailFrom}}
version: 1.0.0
relevantTechniques:
- T1566

{
  "$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/6e0b70d4-0ab8-480e-9707-8ad45fc21a65')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/6e0b70d4-0ab8-480e-9707-8ad45fc21a65')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "Email from previously unseen sender {{EmailFrom}} contains {{UrlCount}} URL(s).",
          "alertDisplayNameFormat": "RedSift - New URL-bearing sender {{EmailFrom}}"
        },
        "alertRuleTemplateName": "6e0b70d4-0ab8-480e-9707-8ad45fc21a65",
        "customDetails": {
          "CorrelationUid": "CorrelationUid",
          "EmailSubject": "EmailSubject",
          "ReturnPath": "EmailReturnPath",
          "UrlCount": "UrlCount",
          "UrlList": "UrlList"
        },
        "description": "'Detects email forensics events that contain one or more URLs where the sender in the from field has not been seen in the previous 14 days, which may indicate phishing activity or a newly observed sender.'\n",
        "displayName": "Red Sift - New email with URL from previously unseen sender",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "EmailFrom",
                "identifier": "FullName"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIp",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "DNS",
            "fieldMappings": [
              {
                "columnName": "DstHostname",
                "identifier": "DomainName"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "AlertPerResult"
        },
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": true,
            "groupByCustomDetails": [
              "EmailSubject"
            ],
            "groupByEntities": [
              "Account"
            ],
            "lookbackDuration": "P1D",
            "matchingMethod": "Selected",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Red%20Sift/Analytic%20Rules/RedSiftEmailUrlFromNewSender.yaml",
        "query": "let lookback = 14d;\nlet recentWindow = 1h;\nlet historicalSenders = RedSiftEmailForensics_CL\n| extend\n    EmailFrom = tostring(column_ifexists(\"EmailFrom\", \"\"))\n| where TimeGenerated between (ago(lookback) .. ago(recentWindow))\n| where isnotempty(EmailFrom)\n| summarize by EmailFrom;\nRedSiftEmailForensics_CL\n| extend\n    EmailFrom = tostring(column_ifexists(\"EmailFrom\", \"\")),\n    EmailSubject = tostring(column_ifexists(\"EmailSubject\", \"\")),\n    EmailReturnPath = tostring(column_ifexists(\"EmailReturnPath\", \"\")),\n    EmailMessageUid = tostring(column_ifexists(\"EmailMessageUid\", \"\")),\n    SrcIp = tostring(column_ifexists(\"SrcIp\", \"\")),\n    DstHostname = tostring(column_ifexists(\"DstHostname\", \"\")),\n    Severity = tostring(column_ifexists(\"Severity\", \"\")),\n    Message = tostring(column_ifexists(\"Message\", \"\")),\n    CorrelationUid = tostring(column_ifexists(\"CorrelationUid\", \"\")),\n    EmailUrls = todynamic(column_ifexists(\"EmailUrls\", \"[]\"))\n| where TimeGenerated >= ago(recentWindow)\n| where isnotempty(EmailFrom)\n| extend UrlCount = array_length(EmailUrls)\n| where UrlCount > 0\n| mv-apply Url = EmailUrls on (\n    summarize UrlSet = make_set(tostring(Url.url_string), 50)\n  )\n| extend UrlList = strcat_array(UrlSet, \", \")\n| join kind=leftanti (historicalSenders) on EmailFrom\n| project\n    TimeGenerated,\n    EmailFrom,\n    EmailSubject,\n    EmailReturnPath,\n    EmailMessageUid,\n    SrcIp,\n    DstHostname,\n    UrlCount,\n    UrlList,\n    Severity,\n    Message,\n    CorrelationUid\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1566"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}