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# lab-4

## User Role Can Be Modified in User Profile

**Difficulty:** Apprentice

### Lab Description

This lab has an admin panel at `/admin`, accessible only to users with a `roleid` of `2`. The role is stored server-side but can be updated via a mass-assignment vulnerability in the profile update endpoint.

**Objective:** Access the admin panel and delete the user `carlos`.

**Credentials:** `wiener:peter`

### Solution

**Step 1 — Capture the email-change response**

Log in as `wiener:peter` and navigate to the account page. Update the email address and capture all requests in Burp Suite. Send the `POST /change-email` request to Repeater.

**Step 2 — Spot the roleid in the response**

Examine the response body from the `/change-email` endpoint. The server returns a JSON representation of the updated user object, which includes:

```json
{
  "username": "wiener",
  "email": "new@email.com",
  "roleid": 1
}
```

The `roleid` field is visible in the response. If the server reflects it back, it may also accept it as input.

**Step 3 — Inject roleid into the request**

In Repeater, add `"roleid": 2` to the JSON request body:

```json
{
  "email": "new@email.com",
  "roleid": 2
}
```

Send the request. The response confirms the update, and navigating back to the main page now shows an **Admin panel** link — the role escalation was successful.

**Step 4 — Delete carlos**

Open the admin panel and delete the user `carlos` to complete the lab.

### Conclusion

The `/change-email` endpoint accepted and applied arbitrary JSON fields from the request body without restriction — a **mass assignment** vulnerability. By injecting `roleid: 2` alongside the expected `email` field, the server silently elevated the account's privileges. Server-side endpoints should only apply updates to explicitly whitelisted fields, never blindly binding all incoming JSON properties to the user object.


---

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