OWASP New Zealand Day 2019

Serverless Authentication with JWT

About Me

Mehul Patel

* Engineer @ Zimbra

* Technical Evangelist

* Auth0 Ambassador

* Mozilla Reps Mentor
* CAC @ Mozilla

* GDG Nashik Organizer

* Rust Hacks @rusthack

@rowdymehul

Agenda

1. Serverless

2. Authentication & Authorization

3. JWT

4. Deployment

Serverless

What is Serverless?

Serverless, is an execution model where the cloud provider is responsible for executing a piece of code by dynamically allocating the resources. The code is typically run inside stateless containers that can be triggered by a variety of events including http requests, database events, queuing services, monitoring alerts, file uploads, scheduled events (cron jobs), etc. The code that is sent to the cloud provider for execution is usually in the form of a function. Hence serverless is sometimes referred to as “Functions as a Service” or “FaaS”.

Serverless

What is Serverless?

Serverless

What is Serverless?

Let me break it down!

Serverless

What is Serverless?

- Serverless is an execution model

- Cloud providers execute the code

- by allocating resources dynamically

- the code runs inside Stateless containers

- triggered by event( http request, cron job)

- code sent to cloud providers are in the form of functions

- hence "Function as a Service" or "Fass"

credits: DZone

Serverless

Traditional Architecture

- we are charged for keeping the server up

even when we are not using

- responsible for uptime and maintenance of the server and all its resources.

- responsible for applying the appropriate security updates

- we need to manage scaling

Serverless

in Serverless?

Serverless

Why Serverless?

Just like wireless internet has wires somewhere, serverless architectures still have servers somewhere.

What ‘serverless’ really means is that, as a developer, you don’t have to think about those servers.

You just focus on code.

Serverless

Serverless Cloud Providers

Serverless

What you can do with serverless application

- Build APIs

- Data processing

- Custom automation

Serverless

Core Concepts

- Functions

- Services

- Events

Authentication & Authorization

Difference

Authentication & Authorization

Serverless

Authentication

Serverless Authentication

Authentication & Authorization

source: dadario.com.br

Serverless

Authorization

Serverless Authorization

Authentication & Authorization

source: dadario.com.br

JSON Web Token

JWT

What is JSON Web Tokens?

- A way to encode information

- Securely communicate JSON Objects

- Secret-based Verification

- Consists of a header, payload and signature

- Self-contained

JWT

JSON Web Token

JWT

The JWT Header

The header is a JSON Object usually consisting of the type( typ ) , which is JWT, and the algorithm used for encrypting the JWT (alg ):

{
  "alg": "HS256",
  "typ": "JWT"
}

JWT

The JWT Payload

The Payload is a JSON object that consists of user defined attributes ( called public claims ) . Some attributes are defined in the standard ( these are called reserved claims ).

{
    // reserved claim
    "iss": "https://myapi.com", 
    // public claim
    "user": "rowdymehul" 
}

JWT

The JWT Signature

The Signature is the encoded header and payload, signed with a secret.

HMACSHA256(
  base64UrlEncode(header) + "." +
  base64UrlEncode(payload),
  secret
)

This accomplishes several tasks at once, including:

Proves the identity of the sender
Ensures the message has not changed

JWT

The JWT Token

A finished token looks like [encoded header].[encoded payload].[signature] :

JWT

The JWT Token

Authentication Flow

Image Source: StackOverflow

How an application uses JWT to verify the authenticity of a user.

Image source: medium.com

OAuth

OAuth 2.0

An open standard for access delegation, commonly used as a way for Internet users to grant websites or applications access to their information on other websites but without giving them the passwords.

OAuth 2.0 roles

Resource Owner: the entity that can grant access to a protected resource. Typically this is the end-user.
Resource Server: the server hosting the protected resources. This is the API you want to access.
Client: the app requesting access to a protected resource on behalf of the Resource Owner.
Authorization Server: the server that authenticates the Resource Owner, and issues Access Tokens after getting proper authorization. In this case, Auth0.

Protocol flow

Deployment

Demo

webtask.io

Demo

/**
* @param context {WebtaskContext}
*/
module.exports = function(context, cb) {
  cb(null, { hello: context.query.name || 'OWASP , Auckland 2019' });
};