Online Invoicing System Cross-site Scripting

Online Invoicing System (OIS) is open source software which is a lean invoicing system for small businesses, consultants and freelancers created using AppGini. In OIS version 4.0 there is a stored XSS which can enables an attacker takeover of the admin account through a payload that extracts a csrf token and sends a request to change password. It has been found that Item description is reflected without sanitization in app/items_view.php which enables the malicious scenario. (2021-01-22, CVE-2021-21260)

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. (2020-12-24, CVE-2020-35676)

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. (2020-12-24, CVE-2020-35677)

BigProf Online Invoicing System (OIS) through 2.6 has XSS that can be leveraged for session hijacking. An attacker can exploit the XSS vulnerability, retrieve the session cookie from the administrator login, and take over the administrator account via the Name field in an Add New Client action. (2020-01-08, CVE-2020-6583)

Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.

The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:

https://server.com/confirmation?message=Transaction+Complete

what results in:

<span>Confirmation: Transaction Complete</span>

In that case the message can be modified to become a valid Javascript code, e.g.:

https://server.com/confirmation?message=<script>dangerous javascript code here</script>

and it will be executed locally by the user's browser with full access to the user's personal application/browser data:

<span>Confirmation: <script>dangerous javascript code here</script></span>