TMA-OFFICE-2.2.4.7.2.1.3

Ensure 'Don't allow Dynamic Data Exchange (DDE) server lookup in Excel' is set to 'Enabled'

AltaNivel 1Automatizadaoffice

Descripción

This policy setting allows controls whether Dynamic Data Exchange (DDE) server lookup is allowed. The DDE protocol is a set of messages and guidelines. It sends messages between applications that share data and uses shared memory to exchange data between applications. Rationale: In an email attack scenario, an attacker could leverage the DDE protocol by sending a specially crafted file to the user and then convincing the user to open the file, typically by way of an enticement in an email. User setting: the audit checks HKEY_USERS\<SID>\SOFTWARE\Policies\Microsoft\office\16.0\excel\security\externalcontent:disableddeserverlookup (REG_DWORD) in every loaded user hive (S-1-5-21-*) and is compliant when each holds 1. It prints 'no-user-hive-loaded' (FAIL) when no user profile is loaded, so scan while users are logged on.

Cómo se verifica

Método de auditoría: Registro de Windows

registry

$sids = @(Get-ChildItem -Path 'Registry::HKEY_USERS' -ErrorAction SilentlyContinue | Where-Object { $_.PSChildName -match '^S-1-5-21-\d+-\d+-\d+-\d+$' } | ForEach-Object { $_.PSChildName }); if ($sids.Count -eq 0) { 'no-user-hive-loaded' } else { $bad = @(); foreach ($s in $sids) { $v = (Get-ItemProperty -Path ('Registry::HKEY_USERS\' + $s + '\SOFTWARE\Policies\Microsoft\office\16.0\excel\security\externalcontent') -Name 'disableddeserverlookup' -ErrorAction SilentlyContinue).'disableddeserverlookup'; if (-not ($null -ne $v -and @(1) -contains [int64]$v)) { $bad += $s + ':disableddeserverlookup=' + $v } }; if ($bad.Count -eq 0) { 'compliant' } else { 'non-compliant: ' + ($bad -join ', ') } }

Salida esperada: compliant

Cómo se corrige

Método de corrección: Guía o parche de infraestructura

Configure through Group Policy (User Configuration): User Configuration\Administrative Templates\Microsoft Excel 2016\Excel Options\Security\Trust Center\External Content\Don’t allow Dynamic Data Exchange (DDE) server lookup in Excel = Enabled

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: officeproductivitycis-l1
Referencia: CIS Microsoft Office Enterprise Benchmark v2.0.0 - 2.2.4.7.2.1.3 Ensure 'Don't allow Dynamic Data Exchange (DDE) server lookup in Excel' is set to 'Enabled'

Verificar este host

Ejecute esto en un equipo que tenga permiso para auditar. El escaneo es de solo lectura.

shell

tmaegis scan --target office