DOM-based XSS WAHS Practice Questions (Page 1)

Questions 1–5

1. 1foundation · easy

   Which of the following is a common DOM source that can be manipulated by an attacker to introduce untrusted data into a web page?

   • AinnerHTML
   • Bdocument.write()
   • Ceval()
   • Ddocument.cookie
   Reveal Solution Discussion Select an answer first
2. 2application · medium

   A developer is fixing a DOM-based XSS issue where `document.referrer` is written to the page using `document.write()`. The application must still display the referring URL to the user for analytics purposes. Which remediation approach is most effective while preserving the feature?

   • AAdd a `Content-Security-Policy` header that blocks `document.write()` entirely
   • BUse `textContent` instead of `document.write()` to insert the referrer value into a pre-existing DOM element
   • CEncode the referrer value with `encodeURIComponent()` before passing it to `document.write()`
   • DStrip all non-alphanumeric characters from the referrer before writing it to the page
   Reveal Solution Discussion Select an answer first
4. 3foundation · easy

   Which of the following is a realistic impact of a DOM-based XSS vulnerability in a banking application?

   • AAn attacker can read the bank's internal network traffic.
   • BAn attacker can directly transfer funds from the victim's account without any user interaction.
   • CAn attacker can modify the DOM to display a fake transfer form and capture credentials.
   • DAn attacker can install malware on the bank's server.
   Reveal Solution Discussion Select an answer first
5. 4application · medium

   A QA engineer is tasked with testing a web application for DOM-based XSS. The application has a feature that reads a value from document.referrer and uses it to populate a search box. The engineer needs to test this vulnerability dynamically. Which approach is the most effective?

   • ACreate a malicious HTML page that sets document.referrer via a link and then opens the target application, observing if the payload executes.
   • BUse a web proxy to modify the Referer header in the HTTP request and check the server response for the payload.
   • CUse a browser extension that automatically replaces document.referrer with a payload in all pages.
   • DUse a static analysis tool to scan the server-side code for the referrer variable.
   Reveal Solution Discussion Select an answer first
6. 5foundation · easy

   Which browser developer tool is most useful for tracing the flow of data from a DOM source to a sink during dynamic testing of a suspected DOM-based XSS?

   • AJavaScript debugger with breakpoints on DOM property reads and writes.
   • BNetwork tab to view HTTP requests and responses.
   • CPerformance tab to measure page load time.
   • DApplication tab to view cookies and local storage.
   Reveal Solution Discussion Select an answer first