> For the complete documentation index, see [llms.txt](https://kryptocoder.gitbook.io/hacking-knowledge/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kryptocoder.gitbook.io/hacking-knowledge/web-exploitation-wip/web-vulnerabilities-wip/http-parameter-pollution-wip.md).

# HTTP Parameter Pollution (WIP)

Manipulate or pollute HTTP requests by injecting multiple parameters with the same name into a single request, potentially allowing to bypass security controls, altering the behavior of the application, or accessing unauthorized data.

We can find a typical example of this vulnerability as follows:

* We send a petition to a login form

{% code overflow="wrap" lineNumbers="true" %}

```bash
https://example.com/login?user=guest&pass=password
```

{% endcode %}

***

* We can create confusion by duplicating the user parameter, which could allow us to get information or even access another account

{% code overflow="wrap" lineNumbers="true" %}

```bash
https://example.com/login?user=admin&user=guest&pass=password
```

{% endcode %}

***

* We can also do this by modifying directly the request parameters

{% code title="Example request" overflow="wrap" lineNumbers="true" %}

```json
{
    "data": {
        "user": "admin",
        "user": "guest",
        "pass": "password"    
    }
}
```

{% endcode %}