Microsoft Sentinel Analytic Rules
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Decoy User Account Authentication Attempt

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Ida4dbc292-87eb-11ec-a8a3-0242ac120002
RulenameDecoy User Account Authentication Attempt
DescriptionThe query detects authentication attempts from a decoy user account.

A decoy user account is explicitly created and monitored to alert the SOC, indicating a malicious activity when the account is in use.
TacticsLateralMovement
TechniquesT1021
Required data connectorsSecurityEvents
WindowsSecurityEvents
KindScheduled
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Hunting Queries/DecoyUserAccountAuthenticationAttempt.yaml
Version2.0.2
Arm templatea4dbc292-87eb-11ec-a8a3-0242ac120002.json
Deploy To Azure
// Enter a reference list of decoy users (usernames) "Case Sensitive"
   let DecoyUserNameList = dynamic (["DecoyUser1","DecoyUser2"]);
SecurityEvent
 | where TargetUserName in (DecoyUserNameList)
 | where EventID in (4624,4625)
 | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by EventID, Computer, TargetUserName, LogonTypeName, IpAddress
 | extend Account_0_Name = TargetUserName
 | extend Host_0_HostName = Computer
 | extend IP_0_Address = IpAddress  
version: 2.0.2
entityMappings:
- fieldMappings:
  - identifier: Name
    columnName: TargetUserName
  entityType: Account
- fieldMappings:
  - identifier: HostName
    columnName: Computer
  entityType: Host
- fieldMappings:
  - identifier: Address
    columnName: IpAddress
  entityType: IP
kind: Scheduled
relevantTechniques:
- T1021
tactics:
- LateralMovement
query: |
  // Enter a reference list of decoy users (usernames) "Case Sensitive"
     let DecoyUserNameList = dynamic (["DecoyUser1","DecoyUser2"]);
  SecurityEvent
   | where TargetUserName in (DecoyUserNameList)
   | where EventID in (4624,4625)
   | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by EventID, Computer, TargetUserName, LogonTypeName, IpAddress
   | extend Account_0_Name = TargetUserName
   | extend Host_0_HostName = Computer
   | extend IP_0_Address = IpAddress    
id: a4dbc292-87eb-11ec-a8a3-0242ac120002
requiredDataConnectors:
- dataTypes:
  - SecurityEvent
  connectorId: SecurityEvents
- dataTypes:
  - SecurityEvent
  connectorId: WindowsSecurityEvents
name: Decoy User Account Authentication Attempt
description: |
  'The query detects authentication attempts from a decoy user account. 
  A decoy user account is explicitly created and monitored to alert the SOC, indicating a malicious activity when the account is in use.'  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Hunting Queries/DecoyUserAccountAuthenticationAttempt.yaml
{
  "$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/a4dbc292-87eb-11ec-a8a3-0242ac120002')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/a4dbc292-87eb-11ec-a8a3-0242ac120002')]",
      "properties": {
        "alertRuleTemplateName": "a4dbc292-87eb-11ec-a8a3-0242ac120002",
        "customDetails": null,
        "description": "'The query detects authentication attempts from a decoy user account. \nA decoy user account is explicitly created and monitored to alert the SOC, indicating a malicious activity when the account is in use.'\n",
        "displayName": "Decoy User Account Authentication Attempt",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "TargetUserName",
                "identifier": "Name"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "Computer",
                "identifier": "HostName"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Hunting Queries/DecoyUserAccountAuthenticationAttempt.yaml",
        "query": "// Enter a reference list of decoy users (usernames) \"Case Sensitive\"\n   let DecoyUserNameList = dynamic ([\"DecoyUser1\",\"DecoyUser2\"]);\nSecurityEvent\n | where TargetUserName in (DecoyUserNameList)\n | where EventID in (4624,4625)\n | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by EventID, Computer, TargetUserName, LogonTypeName, IpAddress\n | extend Account_0_Name = TargetUserName\n | extend Host_0_HostName = Computer\n | extend IP_0_Address = IpAddress  \n",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "LateralMovement"
        ],
        "techniques": [
          "T1021"
        ],
        "templateVersion": "2.0.2"
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}