Which of the following potential vulnerabilities exists in the following code snippet? var myEmail = document.getElementById("formInputEmail").value; if (xmlhttp.readyState==4 &&…

The correct answer is C. DOM-based XSS. This is a textbook example of DOM-based Cross-Site Scripting (XSS). The vulnerability has two parts: (1) the data source is the DOM itself-the value of a form input field is read directly via document.getElementById(), and (2) the sink is innerHTML-the unsanitized value is…

Enterprise Security

Question

Which of the following potential vulnerabilities exists in the following code snippet? var myEmail = document.getElementById("formInputEmail").value; if (xmlhttp.readyState==4 && xmlhttp.status==200) { Document.getElementById("profileBox").innerHTML = "Emails will be sent to " + myEmail + xmlhttp.responseText; }

Options

AJavascript buffer overflow
BAJAX XHR weaknesses
CDOM-based XSS
DJSON weaknesses

How the community answered

(31 responses)

A
6% (2)
B
23% (7)
C
61% (19)
D
10% (3)

Explanation

This is a textbook example of DOM-based Cross-Site Scripting (XSS). The vulnerability has two parts: (1) the data source is the DOM itself-the value of a form input field is read directly via document.getElementById(), and (2) the sink is innerHTML-the unsanitized value is written directly into the page's HTML. If an attacker can control the value of the email field (e.g., by crafting a malicious URL with a prefilled form), they can inject arbitrary HTML or JavaScript (e.g., <script>maliciousCode()</script>) that the browser will execute. Because the exploit occurs entirely in the client-side DOM without a server round-trip, it is specifically classified as DOM-based XSS rather than reflected or stored XSS. JavaScript does not have traditional buffer overflows, and no AJAX response parsing or JSON deserialization is the root cause here.

Topics

#DOM-based XSS#JavaScript#AJAX#web application vulnerabilities

Community Discussion

No community discussion yet for this question.

Full CAS-001 Practice