CVE-2010-4631

Step 1: Identify Vulnerable Parameter: The attacker identifies the vulnerable parameters: countrycode in contact.asp, USERNAME in gateway.asp and cart.asp, and the specific parameter in quote.asp and buyitnow.

Step 2: Craft Malicious Payload: The attacker crafts a malicious JavaScript payload, such as <script>alert('XSS')</script>, designed to execute in the victim's browser.

Step 3: Inject Payload: The attacker injects the malicious payload into the vulnerable parameter via a specially crafted URL. For example: http://example.com/contact.asp?countrycode=<script>alert('XSS')</script>

Step 4: Victim Interaction: The attacker tricks a victim into visiting the crafted URL (e.g., through phishing or social engineering).

Step 5: Payload Execution: The victim's browser receives the malicious URL, processes the injected JavaScript, and executes the payload, leading to the XSS vulnerability being exploited.

The vulnerability stems from insufficient input validation and output encoding of user-supplied data in several ASPilot Pilot Cart 7.3 scripts. Specifically, the application fails to properly sanitize user input provided through parameters like countrycode, USERNAME, and others before rendering it in the HTML response. This allows attackers to inject malicious JavaScript code into these parameters, which is then executed by the victim's web browser when the page is loaded. The root cause is a lack of input validation and output encoding (e.g., HTML entity encoding) for user-controlled parameters. The application trusts user input without proper sanitization, leading to the execution of arbitrary JavaScript.