(Review Questions) Web security

  • Due No Due Date
  • Points None
  1. What are the main differences between XSS and CSRF?
  2. Here are some mitigation techniques. Which attacks do you think each individually can prevent. Attacks we are considering XSS, CSRF, and SQLi.
    a) Content security policy (CSP)
    b) Same-origin policy (SOP)
    c) Client-side code sanitization to remove HTML containing certain tags, such as <script>
    d) Web Application Firewall (WAF)
    e) CSRF token (a random value for each instantiation of the webform)
  3. Assume a web service implements a login form in the following way:
     
    ... 
    <form action="signin.php" method="POST"/>
    <p>
     Username: <input type="text" name="login" /><br /> 
     Password: <input type="text" value="password" />
    </p> 
    </form> 
    <?php $query = "SELECT * FROM users WHERE username = '{$_POST['login']}' AND password= '{$_POST['password']}'"; 
    $result = mysql_query($query); 
    ... ?> 
    ...
    a) Show how can you get the data of all the users in the database.
    b) Give the values of the “login” and the “password” field in the form.
    c) Can you log in to user account without having their password?
    d) How is the website storing their password?
  4. What is CSRF token, and what is it useful for?
  5. Can captcha prevent CSRF? Why/Why not?
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