Content Security Policy (CSP) in Cybersecurity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the directive that controls which sources are allowed to load scripts.

Cybersecurity

Content-Security-Policy: [1] 'self';

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

Astyle-src

Bimg-src

Cscript-src

Dconnect-src

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'img-src' which controls images instead of scripts.

The script-src directive controls which sources are allowed to load JavaScript scripts.

2fill in blank

medium

Complete the code to allow resources only from the same origin.

Cybersecurity

Content-Security-Policy: default-src [1];

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

A'*'

B'none'

C'unsafe-inline'

D'self'

Attempts:

3 left

💡 Hint

Common Mistakes

Using '*' which allows all sources, not just same origin.

The 'self' keyword allows loading resources only from the same origin as the page.

3fill in blank

hard

Fix the error in the CSP header to block all inline scripts.

Cybersecurity

Content-Security-Policy: script-src [1];

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

A'unsafe-inline'

B'none'

C'self'

D'unsafe-eval'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'unsafe-inline' which allows inline scripts.

Using 'none' blocks all script sources including inline scripts.

4fill in blank

hard

Fill both blanks to allow images only from the same origin and trusted domain.

Cybersecurity

Content-Security-Policy: img-src [1] [2];

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

A'self'

Bhttps://trusted.com

C'none'

D'unsafe-inline'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'none' which blocks all images.

The img-src directive allows images from the same origin ('self') and the trusted domain https://trusted.com.

5fill in blank

hard

Fill all three blanks to create a CSP that allows styles from the same origin, scripts only from a CDN, and blocks all inline scripts.

Cybersecurity

Content-Security-Policy: style-src [1]; script-src [2] [3];

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

A'self'

Bhttps://cdn.example.com

C'none'

D'unsafe-inline'

Attempts:

3 left

💡 Hint

Common Mistakes

Including 'unsafe-inline' which allows inline scripts.

This CSP allows styles only from the same origin ('self'), scripts only from the CDN (https://cdn.example.com), and blocks inline scripts by using 'none' alongside the CDN.

Practice

1. What is the main purpose of Content Security Policy (CSP) on a website?

easy

A. To store user passwords securely

B. To speed up the website loading time

C. To change the website's layout and design

D. To control which content the website is allowed to load

Solution

1. Step 1: Understand CSP's role in security

   CSP is designed to restrict what content (like scripts, images) a website can load to prevent harmful content.

2. Step 2: Compare options with CSP purpose

   Only controlling content loading matches CSP's main goal; speeding up or design changes are unrelated.

3. Final Answer:

   To control which content the website is allowed to load -> Option D

4. Quick Check:

   CSP controls content loading = A [OK]

Hint: CSP controls content loading to block harmful scripts [OK]

Common Mistakes:

• Confusing CSP with website speed optimization
• Thinking CSP manages website design
• Assuming CSP stores user data

2. Which HTTP header is used to set a Content Security Policy?

easy

A. X-Content-Type-Options

B. Content-Security-Policy

C. Strict-Transport-Security

D. Cache-Control

Solution

1. Step 1: Identify CSP header name

   The official header to set CSP rules is named Content-Security-Policy.

2. Step 2: Eliminate unrelated headers

   X-Content-Type-Options controls MIME sniffing, Strict-Transport-Security enforces HTTPS, and Cache-Control manages caching, none set CSP.

3. Final Answer:

   Content-Security-Policy -> Option B

4. Quick Check:

   CSP header = Content-Security-Policy [OK]

Hint: CSP header is exactly 'Content-Security-Policy' [OK]

Common Mistakes:

• Confusing CSP header with security headers like HSTS
• Using Cache-Control as CSP header
• Mixing up header names with similar security headers

3. Given this CSP directive:
Content-Security-Policy: script-src 'self' https://trusted.com;
Which script source is allowed to run on the website?

medium

A. Scripts only from https://trusted.com

B. Scripts from any website

C. Only scripts from the website itself and https://trusted.com

D. No scripts are allowed

Solution

1. Step 1: Understand the directive meaning

   The directive script-src 'self' https://trusted.com; means scripts can load from the same origin ('self') and from https://trusted.com.

2. Step 2: Analyze options against directive

   Only scripts from the website itself and https://trusted.com correctly states scripts allowed from the website itself and trusted.com; others are incorrect or too broad.

3. Final Answer:

   Only scripts from the website itself and https://trusted.com -> Option C

4. Quick Check:

   script-src 'self' + trusted.com = A [OK]

Hint: 'self' means own site; listed URLs are allowed too [OK]

Common Mistakes:

• Assuming all external scripts are allowed
• Ignoring the 'self' keyword meaning
• Thinking no scripts are allowed due to strictness

4. A website sets this CSP header:
Content-Security-Policy: default-src 'none'; img-src https://images.com;
Why might images from the website itself not load?

medium

A. Because default-src 'none' blocks all sources except those explicitly allowed

B. Because img-src allows images from all sources

C. Because the header syntax is incorrect

D. Because images are blocked by browser settings

Solution

1. Step 1: Understand default-src 'none'

   The directive default-src 'none' blocks all content sources unless specifically allowed.

2. Step 2: Analyze img-src directive

   Only images from https://images.com are allowed; images from the website itself are not allowed because 'self' is not included.

3. Final Answer:

   Because default-src 'none' blocks all sources except those explicitly allowed -> Option A

4. Quick Check:

   default-src 'none' blocks all except allowed = D [OK]

Hint: default-src 'none' blocks all except listed sources [OK]

Common Mistakes:

• Assuming img-src allows all images by default
• Thinking header syntax is wrong without checking directives
• Blaming browser settings instead of CSP rules

5. You want to allow scripts only from your own site and block inline scripts to prevent XSS attacks. Which CSP directive correctly achieves this?

hard

A. Content-Security-Policy: script-src 'self';

B. Content-Security-Policy: script-src 'self' 'unsafe-inline';

C. Content-Security-Policy: script-src *;

D. Content-Security-Policy: default-src 'none'; script-src 'unsafe-inline';

Solution

1. Step 1: Understand blocking inline scripts

   To block inline scripts, do not include 'unsafe-inline' in the script-src directive.

2. Step 2: Analyze options for script sources

   Content-Security-Policy: script-src 'self'; allows scripts only from the website itself ('self') and blocks inline scripts by omission of 'unsafe-inline'. Content-Security-Policy: script-src 'self' 'unsafe-inline'; allows inline scripts, C allows all scripts, and D allows inline scripts but blocks others.

3. Final Answer:

   Content-Security-Policy: script-src 'self'; -> Option A

4. Quick Check:

   Allow 'self' only, no 'unsafe-inline' = B [OK]

Hint: Exclude 'unsafe-inline' to block inline scripts [OK]

Common Mistakes:

• Including 'unsafe-inline' which allows inline scripts
• Using wildcard * which allows all scripts
• Misunderstanding default-src vs script-src directives