Session vs Token Authentication in 100 Seconds

Summary

This video discusses two main approaches to user authentication: server-side sessions and token-based authentication. Sessions store user data on the server, creating potential vulnerabilities like cross-site request forgery and bottlenecks in distributed systems. Token-based authentication, using JSON Web Tokens (JWT), avoids server storage by keeping tokens client-side, which improves scalability but introduces its own risks, such as token hijacking and difficulties in invalidation. The video concludes by highlighting a 12-week web security coaching program, focusing on modern security practices.

Takeaways

• 🔐 Cookie-based sessions involve storing session IDs on the server, and the session ID is stored in the browser's cookie jar.
• ⚠️ Cross-Site Request Forgery (CSRF) can occur in session-based authentication but is generally mitigated in modern frameworks.
• 📉 A major drawback of session-based authentication is the need to store session IDs in a database or memory, which can be a bottleneck in horizontally scaled cloud systems.
• 🔄 Token-based authentication, like JSON Web Tokens (JWTs), eliminates the need for storing session IDs on the server.
• 🗝️ JWTs are created with a private key on the server and stored in the browser's local storage for client-side management.
• 🚀 JWTs make it more efficient to handle distributed cloud systems as there's no need for a database lookup.
• ⚠️ Tokens can still be vulnerable to hijacking and may be difficult to invalidate after being issued.
• 💡 A key difference between sessions and tokens: sessions are managed server-side, while tokens are managed client-side.
• 🧩 Tokens can't be used for background authentication on the server, limiting some functionalities.
• 📚 The script promotes a web security academy and a 12-week coaching program for mastering web security, including a module on Firebase security.

Q & A

What is the traditional approach to user authentication on the web?

The traditional approach is cookie-based, server-side sessions. The server validates the user's credentials, creates a session in the database, and sends a session ID to the browser, which is stored in the browser's cookie jar.

How does the session ID function in subsequent requests?

The session ID stored in the browser's cookie jar is sent back to the server with each subsequent request, allowing the server to respond with content tailored to the authenticated user.

What are some drawbacks of session-based authentication?

Drawbacks include vulnerability to cross-site request forgery (CSRF) attacks and the need to store session IDs in a database or in server memory, which can become a bottleneck when scaling cloud applications horizontally.

What is cross-site request forgery (CSRF) and how does it affect session-based authentication?

CSRF is an attack where an attacker tricks the user into performing actions on a site they're logged into, such as making payments or changing passwords. Although the risk is low with modern frameworks, it remains a potential issue for session-based authentication.

How does token-based authentication solve the problem of horizontal scaling in cloud applications?

Token-based authentication eliminates the need for database lookups by generating a JSON Web Token (JWT) after login, which is stored in the browser and sent in the authorization header for future requests. The server only needs to validate the JWT signature, reducing the need for database interactions.

What is a JSON Web Token (JWT), and how is it used in token-based authentication?

A JWT is a token created with a private key on the server, which is sent to the browser after login. It is stored in local storage or cookies and sent with each request in the authorization header. The server validates the token to authenticate the user.

What are the potential risks of using token-based authentication?

Tokens can still be hijacked by attackers, and they can be difficult to invalidate once issued. Additionally, tokens can't be used to authenticate a user in the background on the server.

What is the key difference between session-based and token-based authentication?

The key difference is that in session-based authentication, the authentication state is managed on the server, whereas in token-based authentication, the state is managed on the client.

Why is token-based authentication considered more efficient in distributed cloud systems?

Token-based authentication is more efficient because the server only needs to validate the JWT's signature, removing the need for database lookups and allowing better performance in horizontally scaled systems.

What is a key challenge of token-based authentication in terms of token management?

One of the challenges is that tokens are difficult to invalidate once they have been issued, posing a risk if they are compromised.

Outlines

00:00

🔐 Session-based Authentication Overview

This paragraph introduces the concept of session-based authentication, a traditional method used for user login on the web. The process starts when a user submits their credentials (username and password) to a server, which validates the information, creates a session, and sends back a session ID stored in the browser's cookies. The session ID is used in future requests to maintain the authenticated state between the client and the server, making this a 'stateful' process. However, session-based authentication has some vulnerabilities, such as cross-site request forgery (CSRF), and scalability issues, particularly in cloud environments where horizontal scaling is common.

🛡️ Token-based Authentication Explanation

Token-based authentication is introduced as a modern alternative to session-based authentication. Instead of storing a session ID, the server generates a JSON Web Token (JWT) using a private key, which is sent to the client and stored in local storage. Future requests include the JWT in the Authorization header. Token-based authentication is more efficient for cloud-based systems as it eliminates the need for database lookups to manage session states, but it also introduces new challenges, such as token hijacking and the difficulty of invalidating tokens.

⚖️ Sessions vs. Tokens: Key Differences

This section highlights the primary distinction between sessions and tokens. With session-based authentication, the server manages the user's authentication state, storing it in a database or memory, which can cause scalability issues. In contrast, token-based authentication handles the state on the client side, with the server only needing to validate the token's signature. Both approaches have trade-offs in terms of security and efficiency.

📢 Final Thoughts and Course Promotion

The final paragraph wraps up the discussion and introduces a promotional segment for a 12-week web security coaching program, emphasizing the value of group-based learning. The author mentions that they will be teaching a module on Firebase security and invites viewers to check out the course details through a link provided in the description.

Keywords

💡Sessions

Sessions refer to a method of maintaining user authentication by storing a session ID on the server. After a user logs in, the server generates a session ID, which is stored in the browser's cookies. This allows the server to identify and authenticate the user on future requests. The concept is crucial to understanding stateful authentication, where the server maintains the user’s authentication state.

💡Tokens

Tokens, specifically JSON Web Tokens (JWT), are a modern method of handling user authentication. Rather than maintaining session IDs on the server, a token is generated and stored on the client, usually in local storage. On subsequent requests, the token is sent in the authorization header. Token-based authentication is important for distributed systems, as it removes the need for the server to store session data, making it more scalable.

💡Cookie-based Sessions

Cookie-based sessions are a traditional approach to authentication where session IDs are stored in a user’s browser cookies. This method ensures that with every request to the server, the session ID is sent back, allowing the server to authenticate the user. It plays a key role in stateful authentication systems, though it can be vulnerable to attacks like cross-site request forgery (CSRF).

💡JSON Web Token (JWT)

A JWT is a compact, URL-safe token that is used for stateless authentication. It is generated by the server upon user login and contains a signature that can be verified later without looking up the session in a database. This makes JWTs efficient for scaling cloud applications, as no server-side storage is required, but they come with challenges like token hijacking and difficulty in invalidation.

💡Cross-Site Request Forgery (CSRF)

CSRF is a type of attack where a malicious site tricks a logged-in user into performing actions on a website they are authenticated with. The attack relies on the session cookies being automatically sent with every request. While CSRF risks are low in modern frameworks, it’s one of the vulnerabilities of cookie-based session management mentioned in the video.

💡Local Storage

Local storage is a browser-based storage solution where tokens like JWTs can be kept by the client. In contrast to cookies, which are automatically sent with every request, tokens stored in local storage are manually added to requests, typically in the authorization header. This method is important for understanding token-based authentication and its management on the client side.

💡Bearer Token

A bearer token is an authentication token that is sent in the authorization header of an HTTP request. Prefixed with 'Bearer,' it allows the server to verify the user without querying a database for session information. In the video, this term is related to the use of JWTs in token-based authentication.

💡Stateful Authentication

Stateful authentication is an approach where the server maintains the user's authentication state, typically by using sessions stored in a database. Each user’s session ID is matched with a server-side record to verify their identity. This concept contrasts with stateless authentication and is essential for understanding traditional web authentication mechanisms.

💡Stateless Authentication

Stateless authentication refers to managing authentication entirely on the client-side, typically with tokens like JWTs. The server does not store user sessions, instead relying on the client to provide valid tokens with each request. This approach, emphasized in the video, is more efficient for distributed systems but comes with its own set of challenges, such as token revocation.

💡Cloud Applications

Cloud applications are software systems that run on cloud infrastructure, often requiring horizontal scaling to handle large numbers of users. In the video, cloud applications are relevant when discussing the scalability problems with session-based authentication, as maintaining sessions across multiple distributed servers can be challenging.

Highlights

There are two main ways to handle user authentication: sessions and tokens.

The traditional approach is server-side sessions using cookies to store session IDs.

A session ID is saved in the browser's cookie jar and sent with every request.

Sessions create a stateful connection between the client and server.

Sessions are vulnerable to Cross-Site Request Forgery (CSRF) attacks.

One major drawback of sessions is storing session IDs in databases, which can be inefficient in horizontally scaled applications.

Token-based authentication, using JSON Web Tokens (JWT), solves this scalability issue.

JWTs are generated on the server and stored in the client’s local storage.

Subsequent requests include the JWT in the Authorization header with a Bearer prefix.

JWTs eliminate the need for a database lookup, improving efficiency in cloud-based systems.

Tokens are vulnerable to hijacking and can be difficult to invalidate.

Unlike sessions, tokens cannot authenticate users in the background on the server.

The main difference between sessions and tokens: session state is handled server-side, while token state is managed client-side.

Modern frameworks reduce the risk of CSRF attacks, but scaling limitations still exist with sessions.

The video promotes a web security course, mentioning a 12-week group learning program focused on web security.

Transcripts

user authentication there are two main

ways to get the job done

sessions and tokens the traditional

approach on the web is cookie-based

server-side sessions the process begins

with a user filling out their username

and password and then submitting it to a

server which then validates it creates a

session in the database

then responds with a session id the

session id will be saved in the

browser's cookie jar

which is a place in the browser to save

key value pairs that will be sent back

to the server on each subsequent request

it can then respond back with content

designed for the currently logged end

user

in other words we have a stateful

session between the front end client

and backend server this approach works

great but there are some drawbacks it

can be vulnerable to an attack known as

cross-site request forgery where the

attacker points the user to a site

they're logged into to perform

actions they didn't intend to like

submitting a payment or changing their

password

although the risk is very low especially

if you use a modern framework to

implement your code the bigger problem

is that you'll need to store the session

id

in a database or keep it in memory on

the server because most of today's

cloud applications are scaled

horizontally this can be a huge

bottleneck in production

and that brings us to token-based

authentication which solves this problem

but introduces its own set of challenges

the process begins the same with the

client sending its login details to the

server instead of storing a session id

it generates a json web token the jot is

created with a private key on the server

then it's sent back to the browser where

it's normally kept in local storage

on future requests the jot will be added

to the authorization header

prefixed by bearer the server then only

needs to validate the signature there's

no need for a database lookup somewhere

else in the infrastructure

and that's way more efficient when

dealing with a distributed system in the

cloud

however tokens can still be hijacked by

an attacker and they can also be

difficult to invalidate

and they can't be used to authenticate a

user in the background on the server

here's the most important thing to

understand with a session the

authentication state is handled on the

server

while tokens are managed on the client

this has been user authentication in 100

seconds

if you want to master web security check

out web security academy

my friend bartos is launching a 12-week

coaching program

it's not your ordinary course but 12

weeks of high-value group-based learning

and i'm teaching my own module in the

course on firebase security check out

the link in the description to learn

more and i will see you there in a few

weeks thanks for watching