BigProf Online Invoicing System before 3.0 offers a functionality that allows an administrator to move the records of members across groups. The applicable endpoint (admin/pageTransferOwnership.php) lacks CSRF protection, resulting in an attacker being able to escalate their privileges to Administrator and effectively taking over the application.
A CSV injection vulnerability found in Online Invoicing System (OIS) 4.3 and below can be exploited by users to perform malicious actions such as redirecting admins to unknown or harmful websites, or disclosing other clients' details that the user did not have access to.
BigProf Online Invoicing System before 3.1 fails to correctly sanitize an XSS payload when a user registers using the self-registration functionality. As such, an attacker can input a crafted payload that will execute upon the application's administrator browsing the registered users' list. Once the arbitrary Javascript is executed in the context of the admin, this will cause the attacker to gain administrative privileges, effectively leading into an application takeover. This affects app/membership_signup.php and app/admin/pageViewMembers.php.
BigProf Online Invoicing System before 4.0 fails to adequately sanitize fields for HTML characters upon an administrator using admin/pageEditGroup.php to create a new group, resulting in Stored XSS. The caveat here is that an attacker would need administrative privileges in order to create the payload. One might think this completely mitigates the privilege-escalation impact as there is only one high-privileged role. However, it was discovered that the endpoint responsible for creating the group lacks CSRF protection.