XSS

Prompts and answers

• Which XSS vulnerability relies on saving the malicious script?
  Stored XSS
• Which prevalent XSS vulnerability executes within the browser session without being saved?
  Reflected XSS
• What does DOM stand for?
  Document Object Model
• Based on the leading causes of XSS vulnerabilities, what operations should be performed on the user input?
  validation and sanitization
• To prevent XSS vulnerabilities, what operations should be performed on the data before it is output to the user?
  encoding
• Which one of the following characters do you expect to be encoded? ., ,, ;, &, or #?
  &
• Which one of the following characters do you expect to be encoded? +, -, *, <, =, or ^?
  <
• Which function can we use in JavaScript to replace (unsafe) special characters with HTML entities?
  escapeHtml()
• Which function did we use in PHP to replace HTML special characters?
  htmlspecialchars()
• What type of vulnerability is it?
  Reflected XSS
• Use the above exploit against the attached VM. What do you see on the second line after go to?
  /?h#cc
• What is the name of the JavaScript function we used to sanitize the user input before saving it?
  sanitizeHtml()
• Which method did we call in ASP.Net C# to sanitize user input?
  HttpUtility.HtmlEncode()
• What type of vulnerability is it?
  Stored XSS
• Go to the contact page and submit the following message . Next, log in as the Receptionist. What is the name of the key from the displayed key-value pair?
  PHPSESSID
• DOM-based XSS is reflected via the server. (Yea/Nay)
  Nay
• DOM-based XSS happens only on the client side. (Yea/Nay)
  Yea
• Which JavaScript method was used to escape the user input?
  encodeURIComponent()
• Which character does &#x09 represent?
  Tab
• This room used a fictional static site to demonstrate one of the XSS vulnerabilities. Which XSS type was that?
  DOM-based XSS