XSS Room Walkthrough – TryHackMe

Cross-Site Scripting (XSS) is a prevalent web security vulnerability that attackers exploit to inject malicious scripts into seemingly legitimate websites. These scripts then execute within the victim’s browser, potentially compromising their data, hijacking sessions, or even redirecting them to malicious websites.

XSS Room

Answers for this room

1)I completed the Intro to cross site scripting room.

Task 1:

Ans. No Answer needed

Task 2:

2)Which XSS vulnerability relies on saving the malicious script?

Ans. stored xss

3)Which prevalent XSS vulnerability executes within the browser session without being saved?

Ans. reflected xss

4)What does DOM stand for?

Ans. document object model

Task 3:

5)Based on the leading causes of XSS vulnerabilities, what operations should be performed on the user input?

Ans. validation and sanitization

6)To prevent XSS vulnerabilities, what operations should be performed on the data before it is output to the user?

Ans. encoding

Task 4:

7)Which one of the following characters do you expect to be encoded? ., ,, ;, &, or #?

Ans. &

8)Which one of the following characters do you expect to be encoded? +, -, *, <, =, or ^?

Ans. <

9)Which function can we use in JavaScript to replace (unsafe) special characters with HTML entities?

Ans. escapeHtml()

10)Which function did we use in PHP to replace HTML special characters?

Ans. htmlspecialchars()

Task 5:

11)What type of vulnerability is it?

Ans. reflected xss

12)Use the above exploit against the attached VM. What do you see on the second line after go to?

Ans. /?h#cc

Task 6:

13)What is the name of the JavaScript function we used to sanitize the user input before saving it?

Ans. sanitizeHTML()

14)Which method did we call in ASP.Net C# to sanitize user input?

Ans. HttpUtility.HtmlEncode()

Task 7:

15)What type of vulnerability is it?

Ans. stored xss

16)Go to the contact page and submit the following message <script>alert(document.cookie)</script>. Next, log in as the Receptionist. What is the name of the key from the third displayed key-value pair?

Ans. PHPSESSID

Task 8:

17)DOM-based XSS is reflected via the server. (Yea/Nay)

Ans. nay

18)DOM-based XSS happens only on the client side. (Yea/Nay)

Ans. yea

19)Which JavaScript method was used to escape the user input?

Ans. encodeURIComponent()

Task 9:

20)Which character does &#x09 represent?

Ans. tab

Task 10:

21)This room used a fictional static site to demonstrate one of the XSS vulnerabilities. Which XSS type was that?

Ans. dom-based xss

I hope you found this information helpful.

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