InvoiceShelf unauthenticated PHP Deserialization Vulnerability

Description

InvoiceShelf is an open-source web & mobile app that helps you track expenses, payments, create professional invoices & estimates and is based on the PHP framework Laravel. InvoiceShelf has a Remote Code Execution vulnerability that allows remote unauthenticated attackers to conduct PHP deserialization attacks. This is possible when the `SESSION_DRIVER=cookie` option is set on the default InvoiceShelf .env file meaning that any session will be stored as a ciphered value inside a cookie. These sessions are made from a specially crafted JSON containing serialized data which is then ciphered using Laravel's encrypt() function. An attacker in possession of the `APP_KEY` would therefore be able to retrieve the cookie, uncipher it and modify the serialized data in order to get arbitrary deserialization on the affected server, allowing them to achieve remote command execution. InvoiceShelf version `1.3.0` and lower is vulnerable. As it allows remote code execution, adversaries could exploit this flaw to execute arbitrary commands, potentially resulting in complete system compromise, data exfiltration, or unauthorized access to sensitive information.