What Are HTTP Cookies? A Beginner’s Guide to Web Cookies

Whenever someone opens a new website, a pop-up asks whether the user accepts cookies. While many users may find this frustrating, did you know that web cookies are essential for a seamless browsing experience?

In this beginner’s guide, you’ll learn about HTTP cookies, their role, different types, and how to make sure they’re secure. Let’s dive in!

Introduction to HTTP Cookies

HTTP cookies have many synonyms, such as browser cookies, internet cookies, or web cookies. They are small blocks of data. A web server creates these data blocks while an internet user is browsing a website, and a web browser places them on the user’s computer or any other devices used for accessing a website. Multiple cookies can be placed on a user’s device during one session.

Browser cookies are important for several reasons, and sometimes they’re essential for web functions. Here are the main cookie functions:

• Session management

Cookies enable web servers to store session data. For example, storing login credentials ensures that users don’t have to log in when they navigate between website pages.

• Personalization

Cookies ensure a customized user experience by enabling websites to remember user preferences, such as language settings, themes, etc.

• Tracking and analytics

Tracking website user behavior helps collect data for analytics. For example, cookies track visitors’ activity on a website and this data can be used to improve site functionality.

• Stateful sessions

HTTP cookies enable websites to ‘note’ and ‘remember’ various things, such as the contents of a shopping cart, even when the user leaves the page and returns later. This helps maintain a state in stateless HTTP protocols.

• Advertising

Targeted ads are heavily dependent on cookies. Cookies track user behavior and preferences, which helps improve ad relevance to different web users.

• Security

Internet cookies play an important role in web security. They store authentication tokens or other security-related data in order to help validate requests and protect user information.

You may have already heard about HTTP proxies . It’s important to note that if you’re using the same proxy for multiple sites, cookies from different websites can still track your actions across sessions. Apart from this, HTTP proxies and HTTP cookies have very little in common and play completely different roles.

How Do HTTP Cookies Work?

Let’s look into how HTTP cookies work, step by step:

1. Cookie creation

When a user visits a website, the server can send cookies to their browser through the Set-Cookie header in the HTTP response. This header can contain the cookie’s name, value, expiration date, domain attribute, and similar parameters.

For example, this is what a cookie with domain and path attributes might look like:

 `Set-Cookie: userID=12345; expires=Mon, 6 Jan 2025 12:00:00 GMT; path=/; domain=example.com`. 

2. Cookie storage

Once the server sends the cookie, the browser stores it locally. The cookie is saved in a special browser’s storage area.

Each cookie is linked to attributes, such as domain, path, etc. These attributes let the browser know when and under what conditions to send the cookie back to the server. For example, a cookie may be set to work only for certain domains or on specific pages (defined by path value).

3. Cookie sending

When a user browses a website, the browser automatically includes the cookies it has stored in the HTTP request that it sends back to the server.

These cookies are sent in the Cookie header of the request, so the server can identify the user or their session. This way, the server recognizes the user and can maintain their session, remember preferences, or keep the user authenticated throughout the entire session.

4. HTTP cookie usage

The server uses cookie data for many things. For example, tracking user behavior, managing login sessions, or personalizing content.

5. Expiration

HTTP cookies can have a set expiration and be automatically deleted when the day passes. Cookies can also be session-based, which means they’ll be deleted when the user closes their browser.

The browser regularly checks the cookie expiration date and removes any that are expired. Users can also delete cookies manually through browser settings.

Why Do Websites Ask You to Accept Cookies?

Websites ask you to accept cookies due to privacy laws. For example, the General Data Protection Regulation (GDPR) in Europe and the California Consumer Privacy Act (CCPA) in the United States.

These laws require websites to obtain consent from users before storing cookies. This is especially relevant for cookies that are used for tracking and personalizing content, as they can collect personal data.

Accepting cookies provides numerous benefits for users, such as:

• Personalized experience

Cookies remember user preferences, language, and other settings across sessions, so users don’t have to set them every time they visit a website.

• Faster browsing

Cookies store user’s session data in the web browser, so users don’t need to log in or re-enter their details every time.

• Targeted advertisement

Due to cookies, users see relevant ads across the web.

In short, cookies save a lot of time for web users and make their experience online much smoother.

Types of Cookies

There are many types of cookies. Each type has a different role or functionality. Here are the main cookie types:

• Session cookies

Temporary cookies are stored only for the duration of a user’s visit to a website and are deleted when the user closes their browser. These cookies help with session management.

• Persistent cookies

These cookies have a termination date set by the website, so they remain on the user’s device even when the browser is closed. Persistent cookies are used to remember login details, user preferences, or various settings between website visits.

• HttpOnly cookies

Cookies that cannot be accessed by the client-side scripts, only by the server. HttpOnly Cookies are used to store sensitive data. For example, user’s session identifiers to enhance security.

• Secure cookies

The kind of cookies that are only sent over secure HTTPS connections. These cookies ensure that the cookie data is sent securely in order to prevent intervention by malicious parties.

• First-party cookies

A website a user is visiting sets these cookies. They help the site to remember user settings and preferences.

• Third-party cookies

Contrary to first-party cookies, these are set by a domain different from the website a user is browsing. Third-party cookies are mainly used to track users across different websites for analytical purposes and targeted advertising. These cookies can be sent with cross-site requests, enabling seamless user sessions across different domains.

Security Risks of Cookies

HTTP cookies originally aren’t secure, but they can be made so through proper handling and implementation. Without proper security measures, cookies can be tampered with, hijacked, and pose other security risks.

One of the potential risks is session hijacking. An attacker can steal a user’s session cookie via cross-site scripting and access sensitive user’s data by impersonating them.

Cross-site scripting (XSS) is another risk that can make cookies vulnerable to theft. To avoid this risk, cookies have to be marked as HttpOnly, so they won’t be accessible via JavaScript.

Unprotected cookies that store sensitive data can be altered by an attacker. This risk is called cookie tampering.

Fortunately, cookies can be made secure and avoid the mentioned risks. For that, cookies should only be transmitted over HTTPS connections that cannot be read by JavaScript by setting the Secure and HttpOnly flags.

Cookie lifespan should also be limited for security reasons. Regularly clearing cookies can help ensure there are no active cookies for too long. Tracking cookies tend to have a long lifespan, so they are vulnerable to cookie hijacking.

Accessing websites through HTTP and HTTPS proxies can also enhance security, as this way servers wouldn't be able to identify the user through their IP address.

Managing Cookies

Users can manage cookies via their web browsers. They can view cookie information and familiarize themselves with various cookies that are stored in their web browser, manage HTTP cookie settings, and also delete them.

Google Chrome Cookie Settings

Here’s how to view the cookies stored on the Google Chrome web browser: right-click the page, select Inspect , go to the Application tab, and look at the Cookies section. This will demonstrate all the cookies set by the site and their attributes.

Chrome users can also manage their cookie preferences. For example, Chrome users can set the browser to allow all cookies and block third-party cookies or all cookies. The browser also enables users to clear cookies when the user closes Chrome.

All of these actions can be done by accessing Privacy and security settings and then choosing Cookies and other site data.

Mozilla Firefox Cookie Settings

Here’s how to view the cookies stored on Firefox: right-click and select Inspect, go to the Storage tab, and look under Cookies to see all cookies and their associated domains.

Mozilla Firefox users can also access their cookie settings by going to Settings and then clicking on Privacy & Security from the left-hand sidebar.

Users can manage their cookie preferences by choosing one of three options:

• Standard — allows most cookies.
• Strict — blocks cookies and trackers but may affect web functionalities.
• Custom — allows choosing the settings.

Under the same Privacy & Security settings, Firefox users can also view and delete cookies, or set the web browser to delete cookies automatically when Firefox is closed.

Conclusion

HTTP cookies play an important role in building a seamless browsing experience. They can ensure web users don’t have to log in every single time they refresh a page, and user’s information is stored for future usage.

Cookies are created by web servers and stored by browsers. Users can manage their cookies via browser settings. Some cookies have a set expiration date, while others expire as soon as a user’s session ends. Users can also manually delete their cookies.

User consent for cookies is necessary due to various privacy laws that vary slightly across countries. Users should accept cookies because they ensure the best browsing experience.

However, web cookies aren’t inherently secure. They have to be secured when implementing cookies and maintaining them. Only then can users be sure their private data will be properly secured.