Security best practices in Ruby on Rails - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable strong parameters in a Rails controller.

Ruby on Rails

def user_params
  params.require(:user).[1](:name, :email, :password)
end

Drag options to blanks, or click blank then click option'

Apermit

Bfetch

Callow

Daccept

Attempts:

3 left

💡 Hint

Common Mistakes

Using fetch instead of permit causes errors.

Not using strong parameters can lead to security risks.

The permit method specifies which parameters are allowed for mass assignment, protecting against unwanted data changes.

2fill in blank

medium

Complete the code to protect against Cross-Site Request Forgery (CSRF) attacks in a Rails controller.

Ruby on Rails

class ApplicationController < ActionController::Base
  [1]
end

Drag options to blanks, or click blank then click option'

Aprotect_from_forgery with: :exception

Binclude ActionController::Helpers

Cbefore_action :authenticate_user!

Dskip_before_action :verify_authenticity_token

Attempts:

3 left

💡 Hint

Common Mistakes

Skipping CSRF verification disables protection.

Using unrelated filters does not protect against CSRF.

The protect_from_forgery with: :exception line enables CSRF protection by raising an exception on unverified requests.

3fill in blank

hard

Fix the error in the code to safely escape user input in a Rails view.

Ruby on Rails

<%= [1] %>

Drag options to blanks, or click blank then click option'

Araw @user.name

Bsanitize @user.name

Chtml_safe @user.name

[e-mail]

Attempts:

3 left

💡 Hint

Common Mistakes

Using raw or html_safe can cause XSS vulnerabilities.

Not escaping user input risks security.

The sanitize helper cleans user input to prevent injection of harmful HTML or scripts.

4fill in blank

hard

Fill both blanks to configure secure cookies in Rails.

Ruby on Rails

Rails.application.config.session_store :cookie_store, key: '_app_session', secure: [1], httponly: [2]

Drag options to blanks, or click blank then click option'

Atrue

Bfalse

Cnil

Dauto

Attempts:

3 left

💡 Hint

Common Mistakes

Setting secure or httponly to false weakens security.

Leaving these options unset may expose cookies.

Setting secure: true ensures cookies are sent only over HTTPS. httponly: true prevents JavaScript access to cookies, improving security.

5fill in blank

hard

Fill all three blanks to implement Content Security Policy (CSP) headers in Rails.

Ruby on Rails

Rails.application.config.content_security_policy do |policy|
  policy.default_src [1]
  policy.script_src [2]
  policy.style_src [3]
end

Drag options to blanks, or click blank then click option'

A['self']

B['https://trusted.cdn.com']

C['unsafe-inline']

D['none']

Attempts:

3 left

💡 Hint

Common Mistakes

Using ['none'] blocks all content and breaks the app.

Allowing 'unsafe-inline' scripts is risky but sometimes needed for styles.

The CSP configuration restricts sources for content. default_src ['self'] allows content only from the same origin. script_src ['https://trusted.cdn.com'] allows scripts from a trusted CDN. style_src ['unsafe-inline'] permits inline styles when necessary.

Practice

1. Which Rails feature helps prevent unwanted or dangerous user input from being saved to the database?

easy

A. Strong Parameters

B. Active Record Callbacks

C. Action Mailer

D. Asset Pipeline

Solution

1. Step 1: Understand user input control

   Strong Parameters allow you to specify which attributes are allowed from user input, preventing mass assignment vulnerabilities.

2. Step 2: Identify the correct Rails feature

   Active Record Callbacks and others do not control input filtering; only Strong Parameters do.

3. Final Answer:

   Strong Parameters -> Option A

4. Quick Check:

   User input filtering = Strong Parameters [OK]

Hint: Strong Parameters filter user input safely [OK]

Common Mistakes:

• Confusing callbacks with input filtering
• Thinking Asset Pipeline handles security
• Assuming Action Mailer controls input

2. Which line correctly enables CSRF protection in a Rails controller?

easy

A. enable_csrf_protection!

B. protect_from_forgery with: :exception

C. csrf_protect true

D. use_csrf_protection = true

Solution

1. Step 1: Recall Rails CSRF protection syntax

   The correct method to enable CSRF protection is protect_from_forgery with: :exception in controllers.

2. Step 2: Check other options for validity

   Other options are not valid Rails syntax and will cause errors or have no effect.

3. Final Answer:

   protect_from_forgery with: :exception -> Option B

4. Quick Check:

   CSRF protection syntax = protect_from_forgery [OK]

Hint: Use protect_from_forgery with: :exception [OK]

Common Mistakes:

• Using non-existent methods for CSRF
• Forgetting to add CSRF protection
• Misnaming the method or options

3. Given this Rails view code:

<%= raw @user.name %>

What security risk exists if @user.name contains HTML tags?

medium

A. Cross-Site Scripting (XSS) attack

B. SQL Injection

C. Mass Assignment

D. Denial of Service

Solution

1. Step 1: Understand output escaping in Rails views

   Using <%= %> escapes HTML by default, but if raw HTML is inserted, it can cause XSS.

2. Step 2: Identify the risk of unescaped HTML in user input

   If @user.name contains HTML tags and is not escaped, it can run malicious scripts in the browser, causing XSS.

3. Final Answer:

   Cross-Site Scripting (XSS) attack -> Option A

4. Quick Check:

   Unescaped HTML in views = XSS risk [OK]

Hint: Unescaped user input risks XSS attacks [OK]

Common Mistakes:

• Confusing XSS with SQL Injection
• Assuming Rails never escapes output
• Ignoring HTML tags in user input

4. You see this code in a Rails controller:

params.require(:user).permit(:name, :email)

But users report they can update admin-only fields. What is the likely problem?

medium

A. CSRF protection is disabled

B. The controller action is missing

C. Strong Parameters are not used correctly

D. The database schema is incorrect

Solution

1. Step 1: Analyze the use of Strong Parameters

   The code shows permitted params, but if the controller does not use this filtered params hash for updating, mass assignment can happen.

2. Step 2: Identify why admin-only fields update

   If the controller uses unfiltered params or merges extra params, Strong Parameters are bypassed, causing security issues.

3. Final Answer:

   Strong Parameters are not used correctly -> Option C

4. Quick Check:

   Mass assignment issue = incorrect Strong Parameters use [OK]

Hint: Always use filtered params for updates [OK]

Common Mistakes:

• Assuming CSRF causes mass assignment
• Ignoring how params are passed to update
• Blaming database instead of controller code

5. You want to ensure all Rails app traffic is secure and user data is protected. Which combination of practices is best?

hard

A. Only use HTTPS and ignore CSRF and output escaping

B. Disable CSRF protection, use HTTP, and sanitize database inputs

C. Use HTTP, skip escaping output, and rely on user validation

D. Force HTTPS, enable CSRF protection, and escape all output

Solution

1. Step 1: Identify key security practices for web apps

   Forcing HTTPS encrypts data in transit, CSRF protection stops fake requests, and escaping output prevents XSS.

2. Step 2: Evaluate each option's security coverage

   Force HTTPS, enable CSRF protection, and escape all output covers all three essential protections. Others disable or ignore important protections, increasing risk.

3. Final Answer:

   Force HTTPS, enable CSRF protection, and escape all output -> Option D

4. Quick Check:

   HTTPS + CSRF + escaping = best security [OK]

Hint: Combine HTTPS, CSRF, and escaping for strong security [OK]

Common Mistakes:

• Ignoring CSRF protection importance
• Thinking HTTPS alone is enough
• Skipping output escaping