WWBN AVideo: Authenticated wallet credit bypass in AuthorizeNet processPayment endpoint

Summary

plugin/AuthorizeNet/processPayment.json.php credits the logged-in user's wallet based only on the attacker-controlled amount POST parameter.

The endpoint contains a TODO for real Authorize.Net charging, hardcodes $paymentSuccess = true, and then calls YPTWallet::addBalance() without validating any Authorize.Net transaction, webhook signature, hosted payment token, nonce, or server-side payment record.

This allows any logged-in user to add arbitrary funds to their own AVideo wallet when the AuthorizeNet and YPTWallet plugins are enabled.

Details

Affected file:

plugin/AuthorizeNet/processPayment.json.php

Relevant code:

$amount = isset($_POST['amount']) ? floatval($_POST['amount']) : 0;
$userData = isset($_POST['userData']) ? $_POST['userData'] : [];

if ($amount <= 0) {
    echo json_encode(['error' => 'Invalid amount']);
    exit;
}

// TODO: Implement payment logic using Authorize.Net API
// Example: Call Authorize.Net API here
// $result = $plugin->chargePayment($amount, $userData);

// Simulate payment success for now
$paymentSuccess = true;
$users_id = @User::getId();

if ($paymentSuccess && !empty($users_id)) {
    $walletPlugin = AVideoPlugin::loadPluginIfEnabled("YPTWallet");
    if ($walletPlugin) {
        $walletPlugin->addBalance($users_id, $amount, 'Authorize.Net one-time payment');
        echo json_encode(['success' => true, 'result' => 'Payment processed and wallet updated']);
        exit;
    }
}

Vulnerable flow:

1. $_POST['amount'] is read from the client.
2. The endpoint only checks that the amount is greater than zero.
3. The real Authorize.Net charge is not performed.
4. $paymentSuccess is hardcoded to true.
5. The logged-in user's wallet is credited with the client-supplied amount.

There is no verification of:

• Authorize.Net transaction ID
• payment token
• webhook signature
• pending payment record
• expected server-side amount
• currency
• duplicate transaction/replay state

PoC

Prerequisites:

• AVideo with AuthorizeNet plugin enabled
• YPTWallet plugin enabled
• Attacker has any valid user account

Steps:

1. Log in as a low-privileged user.
2. Open the wallet page and record the current balance.
3. Send the following request with the user's authenticated session cookie:

  curl -i -s -b 'PHPSESSID=<user_session>' \
    -X POST 'https://target.example/plugin/AuthorizeNet/processPayment.json.php' \
    --data 'amount=9999&userData[note]=poc'

4. The endpoint returns:

  {"success":true,"result":"Payment processed and wallet updated"}

5. Refresh the wallet page.
6. The wallet balance is increased by 9999.

No Authorize.Net hosted payment page, card payment, transaction confirmation, webhook, or server-side payment validation is required.

Impact

A normal authenticated user can mint arbitrary wallet balance.

Depending on the target site's configuration, this may allow the attacker to:

• purchase paid videos or subscriptions without payment
• abuse any feature backed by YPTWallet
• transfer fake funds to other users
• manipulate accounting or payout-related workflows
• bypass monetization controls

Recommended fix

• Remove or disable processPayment.json.php if it is obsolete.
• Never credit wallet balance from client-supplied amount alone.
• Use the existing Authorize.Net hosted token / webhook / transaction reconciliation flow.
• Require a verified Authorize.Net transaction ID and server-side amount lookup before calling addBalance().
• Add regression tests proving arbitrary POSTs cannot credit a wallet.