Java Application Security Practices

⚡️ Secure by Design: Empowering Java Developers with Best Practices. ⚡️

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This repository provides practical examples and code snippets aimed at helping Java developers implement security best practices. It covers key topics such as security design principles, authentication and authorization, API security, Java process security, common attack mitigations, and security testing - all essential for building secure Java applications.

These examples are designed to complement the curriculum of the 📚 Application Security for Java Developers Course.

If you're looking to take your skills to the next level, 🎓 enroll now and master the art of secure coding in Java!

For more resources and insights, feel free to visit my website.

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Content

• Security Concepts
• Project Modules
• Architectural Diagrams
  • Software Architecture Diagram
  • Sequence Diagram
• Technology Stack
• SetUp
• Security Checks
  • OWASP Dependency-Check
  • SpotBugs with FindSecBugs Plugin
  • Zed Attack Proxy (ZAP)
• License

Security Concepts

Among the security concepts demonstrated in this project:

• Security Design Principles
  • Least privilege
  • Defense in depth
  • Fail securely
  • Compartmentalization
• OAuth 2.0 Grant Types:
  • Password Flow
  • Client Credentials Flow
  • Authorization Code Flow
  • Authorization Code Flow with Proof Key for Code Exchange (PKCE)
• API and Microservices Security
  • Token introspection
  • JSON Web Key Set (JWKS)
  • Roles-based access control
• Java Process Security
  • Input data validation and sanitization
  • Handling input files from external sources
  • Security logging best practices
  • Content Security Policy (CSP)
  • Cross-Origin Resource Sharing (CORS)
  • HTTP security headers (e.g., Strict-Transport-Security, X-XSS-Protection, X-Frame-Options)
  • Java deserialization
• Security Testing
  • Software Composition Analysis (SCA)
  • Static Application Security Testing (SAST)
  • Dynamic Application Security Testing (DAST)

Project Modules

Below is a breakdown and description of each module in the current project.

Module	Description
pizza-order-*, pizza-cooking-*, pizza-delivery-*	These modules represent 3 microservices and their APIs (Pizza Cooking, Delivery, and Order) that demonstrate various OAuth 2.0 flows (e.g., token introspection, JWKS, client credentials), roles-based access control and security logging concepts.
security-feign-logger-enricher	Enriches and enables standard Feign client logging with additional custom Mapped Diagnostic Context (MDC) attributes (e.g., correlation ID) using SLF4J's MDC.
security-slf4j-logger-enricher	Enriches SLF4J-based logging with security-specific attributes (e.g., remote host, remote port, user agent, request URI, request method, correlation ID) using SLF4J's MDC.
security-token-client-credentials-fetcher	Fetches tokens from the Identity Provider (IdP) using the client credentials flow.
security-token-introspection	Introspects and validates access tokens using the IdP's token introspection endpoint. Additionally, it disables security for specific /public endpoints (e.g., OpenAPI definition endpoint), configures CORS and Content Security Policy (CSP), adds HTTP security headers, and parses JWT claim roles, adding them as granted authorities.
security-token-jwks	Handles JSON Web Key Set (JWKS) validation and signature verification of JWT tokens using the IdP's JWKS endpoint. Additionally, it disables security for specific /public endpoints (e.g., OpenAPI definition endpoint) and parses JWT claim roles, adding them as granted authorities.
serialization-deserialization	Demonstrates security risks in serialization and deserialization, including exploits like Java class deserialization attacks, XML external entities, YAML bombs, and ZIP bombs.

Architectural Diagrams

Software Architecture Diagram

This software architecture diagram illustrates the microservices as components within the system and highlights key security aspects, including OAuth 2.0 flows (e.g., Token introspection, JWKS) and endpoint roles checks.

Sequence Diagram

sequenceDiagram
actor User
User->>IdP: Authenticate and fetch JWT (authorization code flow)
User->>Pizza Order Service: Submit order with JWT as HTTP Bearer token
Pizza Order Service->>IdP: Introspect JWT to verify validity
Pizza Order Service->>Pizza Order Service: Check user roles/permissions
Pizza Order Service->>Pizza Cooking Service: Submit cooking order with JWT as HTTP Bearer token
Pizza Cooking Service->>IdP: Fetch JWKS keys (if missing or expired) for local JWT validation
Pizza Cooking Service->>Pizza Cooking Service: Validate JWT signature using JWKS
Pizza Cooking Service->>Pizza Cooking Service: Check user roles/permissions

Note right of Pizza Cooking Service: Pizza is cooked ...

Pizza Cooking Service->>IdP: Fetch JWT (client credentials flow)
Pizza Cooking Service->>Pizza Delivery Service: Submit delivery order with JWT as HTTP Bearer token
Pizza Delivery Service->>IdP: Fetch JWKS keys (if missing or expired) for local JWT validation
Pizza Delivery Service->>Pizza Delivery Service: Validate JWT signature using JWKS
Pizza Delivery Service->>Pizza Delivery Service: Check user roles/permissions
Pizza Delivery Service->>Pizza Delivery Service: Confirm order delivered
Pizza Delivery Service->>Pizza Order Service: Send order status update
Pizza Order Service->>IdP: Introspect JWT to verify validity
Pizza Order Service->>Pizza Order Service: Check user roles/permissions
Pizza Order Service->>Pizza Order Service: Update order status

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Technology Stack

This project includes the following technologies, frameworks, and libraries:

• Spring Boot
• Spotless as a code formatter
• Docker compose
• Keycloak as an Identity and Access Management solution
• OWASP Dependency-Check as a Software Composition Analysis (SCA) tool
• Spotbugs with FindSecBugs plugin as a Static Application Security Testing (SAST) tool
• The Zed Attack Proxy (ZAP) as a Dynamic Application Security Testing (DAST) tool
• OWASP WebGoat a deliberately insecure application

SetUp

Tools to Download and Install

Please ensure you have properly downloaded, installed, and configured the following tools:

Tool	Link
JDK 21	Download (i.e., latest LTS)
Docker	Download
Postman	Download
curl command line	Download
jq command line	Download

The course is developed to work best on GNU/Linux. However, if you prefer to use a Windows machine, you can use one of the following alternatives to properly execute the bash scripts:

• GIT bash
• Cygwin
• Windows Subsystem for Linux (WSL)

Compile, Run Tests, and Package

To compile the project, run tests, and package it, use the following command:

./mvnw clean package

Bootstrap Services with Docker

Note: Please ensure that the Docker daemon is running; otherwise, the commands will not execute successfully.

1. Run the following command to start the Keycloak service in Docker:

   ./bootstrap-keycloak.sh

2. To start the Pizza application, which includes multiple microservices running in Docker, execute:

   ./bootstrap-pizza-application.sh

3. Next, run the following command to start the OWASP WebGoat application in Docker:

   ./bootstrap-webgoat.sh

4. Finally, check that all Docker containers are up and running by executing:

   docker ps -a

Keycloak Configuration

To set up a basic Keycloak configuration, run the following script:

./keycloak-init.sh

The script creates OAuth 2.0 clients, users, and roles under the master realm and assigns the roles to the users:

Type	Name	Password	Purpose
User	demo_user	Test1234!	Used for authorization code flow with PKCE.
Client ID	demo_public_client	6EuUNXQzFmxu6xwPHDvvoh56z1uzrBMw	Used for authorization code flow.
Client ID	demo_private_client	6EuUNXQzFmxu6xwPHDvvoh56z1uzrBMw	Used for client credentials flow.

This setup utilizes Keycloak's REST API to perform these operations and provides output at each step, ensuring efficient user and client management within the Keycloak environment.

Services Overview via UI

Open a browser and navigate to http://localhost:9090 to access the Keycloak UI (using the credentials admin:admin).

Open a browser and navigate to http://localhost:9090/realms/master/.well-known/openid-configuration to access the Keycloak OpenID Connect configuration.

Open a browser and navigate to http://localhost:18080/public/swagger-ui/index.html to access the Pizza Order OpenAPI definition.

Open a browser and navigate to http://localhost:28080/public/swagger-ui/index.html to access the Pizza Cooking OpenAPI definition.

Open a browser and navigate to http://localhost:38080/public/swagger-ui/index.html to access the Pizza Delivery OpenAPI definition.

Open a browser and navigate to http://localhost:48080/WebGoat/login to access the OWASP WebGoat UI.

Local Tests with Postman

1. Open Postman and import the Postman collections.
2. To simulate a basic test scenario, follow these steps in the given sequence:

• a) Fetch the JWT token using either:
  • The Password Flow:

    POST http://localhost:9090/realms/master/protocol/openid-connect/token
    

  • Or the Client Credentials Flow:

    POST http://localhost:9090/realms/master/protocol/openid-connect/token
    

  • Or the Authorization Code Flow with PKCE:

    POST http://localhost:9090/realms/master/protocol/openid-connect/auth
    

• b) Initiate an order request to the pizza-order-service:

  POST http://localhost:18080/pizza/orders
  

Security Checks

OWASP Dependency-Check

OWASP Dependency-Check is an open-source Software Composition Analysis (SCA) tool that identifies vulnerabilities in project dependencies, helping reveal and address known security risks.

To check for potential dependency vulnerabilities, execute the following command:

./mvnw clean compile org.owasp:dependency-check-maven:check

Note: The first run of this command might take a significant amount of time (e.g., from a couple of minutes to even tens of minutes, depending on the internet connection) to initially download the NVD Data Feeds hosted by NIST.

SpotBugs with FindSecBugs Plugin

Spotbugs is an open-source static analysis tool that detects bugs in Java programs by analyzing bytecode.

With the help of the FindSecBugs plugin plugin, it can be used as a Static Application Security Testing (SAST) tool to identify security vulnerabilities in Java applications.

To check for potential code vulnerabilities, execute the following command:

./mvnw clean compile spotbugs:check

Zed Attack Proxy (ZAP)

The Zed Attack Proxy (ZAP) is an open-source Dynamic Application Security Testing (DAST) tool specifically designed for identifying vulnerabilities in applications during runtime.

To check for API security vulnerabilities, execute the following command:

./zap-scan.sh

The command starts ZAP in Docker, launches an API scan using the zap-api-scan rules against one of the services, and saves the scan report in the ./zap/reports folder.

License

This project is licensed under the Apache License, Version 2.0.

Please see the LICENSE file for full license.

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 * Application Security for Java Developers
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