Introduction
In today’s fintech landscape, ensuring that your banking application adheres to compliance standards like PCI-DSS (Payment Card Industry Data Security Standard) is critical. This guide walks you through designing a secure, three-tier bank web application on Microsoft Azure using PCI-DSS compliance principles.
We’ll set up a three-tier architecture:
- Frontend VM (Node.js and NPM)
- Backend VM (Java JDK)
- Database VM (MySQL Database)
The architecture will include a single VNet with three subnets, three NSGs for network security, and a strong firewall strategy.
Overview of Architecture
Key Components:
-
Virtual Network (VNet):
- 3 Subnets:
Frontend Subnet
,Backend Subnet
, andDatabase Subnet
.
- 3 Subnets:
-
Virtual Machines (VMs):
- VM1: Hosts Node.js and NPM (Frontend)
- VM2: Hosts Java JDK (Backend)
- VM3: Hosts MySQL (Database)
-
Network Security Groups (NSGs):
-
Frontend NSG
: Protects the frontend. -
Backend NSG
: Protects the backend. -
Database NSG
: Secures database access.
-
-
PCI-DSS Compliance:
- Secure transmission of sensitive data.
- Strong firewall configuration.
- Segmented architecture to limit lateral movement.
Step 1: Create the Virtual Network (VNet)
- Log into Azure Portal.
-
Create a Virtual Network:
- Navigate to Networking > Virtual Networks > Create.
- Name:
BankApp-VNet
. - Address Space:
192.168.0.0/16
. - Subnets:
-
Frontend Subnet
:192.168.2.0/24
. -
Backend Subnet
:192.168.1.0/24
. -
Database Subnet
:192.168.0.0/24
.
-
- Click Review + Create.
Step 2: Create Virtual Machines
VM1: Frontend (Node.js and NPM)
- Navigate to Compute > Virtual Machines > Create.
-
Configuration:
- Name:
Frontend-VM
. - Size: Standard_B2s (or equivalent).
- Image: Ubuntu Server 22.04.
- Subnet:
Frontend Subnet
.
- Name:
- Install Node.js and NPM:
sudo apt update && sudo apt upgrade -y
sudo apt install -y nodejs npm
node -v
npm -v
VM2: Backend (Java JDK)
- Repeat the steps above for
Backend-VM
:- Subnet:
Backend Subnet
.
- Subnet:
- Install Java JDK:
sudo apt update && sudo apt upgrade -y
sudo apt install -y openjdk-17-jdk
java -version
VM3: Database (MySQL)
- Create
Database-VM
:- Subnet:
Database Subnet
.
- Subnet:
- Install MySQL:
sudo apt update && sudo apt upgrade -y
sudo apt install -y mysql-server
sudo mysql_secure_installation
Step 3: Configure Network Security Groups (NSGs)
Frontend NSG
- Navigate to Networking > Network Security Groups > Create.
- Configure rules:
- Allow HTTP (80) and HTTPS (443) inbound.
- Deny all other inbound traffic.
- Outbound: Allow only to backend subnet.
Backend NSG
- Create another NSG for
Backend-VM
:- Allow TCP port 8080 from frontend subnet.
- Deny all other inbound traffic.
- Outbound: Allow only to database subnet.
Database NSG
- Create the final NSG for
Database-VM
:- Allow MySQL (port 3306) inbound from backend subnet.
- Deny all other inbound traffic.
- Outbound: Deny all (or allow restricted outbound).
Step 4: Application Deployment
Frontend Deployment
- Set up your Node.js app on Frontend-VM:
mkdir bank-frontend
cd bank-frontend
npm init -y
npm install express
-
Create a sample
index.js
file:
const express = require('express');
const app = express();
const PORT = 80;
app.get('/', (req, res) => res.send('Bank Frontend Running!'));
app.listen(PORT, () => console.log(`Server running on port ${PORT}`));
- Run the application:
node index.js
Backend Deployment
-
Create a sample Java REST API on Backend-VM:
- Write and compile your REST API (e.g., using Spring Boot or JAX-RS).
Database Configuration
-
Connect the Backend API to the MySQL Database:
- Create a database for your bank application:
CREATE DATABASE bank_app; CREATE USER 'bank_user'@'%' IDENTIFIED BY 'secure_password'; GRANT ALL PRIVILEGES ON bank_app.* TO 'bank_user'@'%'; FLUSH PRIVILEGES;
Step 5: Implement PCI-DSS Controls
1. Data Encryption
- Enable SSL/TLS for communication between components:
- Install Let's Encrypt SSL certificates for the frontend server.
- Configure MySQL to use SSL for secure database connections.
2. Secure Authentication
- Use strong passwords for all VMs and database users.
- Configure Azure Key Vault to store sensitive secrets like database credentials.
3. Logging and Monitoring
- Enable Azure Monitor to log network traffic and application activity.
- Set up alerts for unusual behavior or unauthorized access attempts.
4. Segmentation
- Subnets are already segmented; ensure NSG rules strictly enforce this segmentation.
Step 6: Test and Validate
Test Connectivity
- Verify that:
- Frontend can communicate with the backend via the
Backend NSG
rules. - Backend can connect to the database securely using
Database NSG
.
- Frontend can communicate with the backend via the
Run PCI-DSS Tests
- Use tools like AlienVault OSSIM or OpenVAS to validate compliance.
Step 7: Secure the Environment
- Regularly update VMs and software.
- Enable Azure Backup to back up critical data.
- Conduct periodic penetration tests to identify vulnerabilities.
Conclusion
This architecture ensures a secure, scalable, and PCI-DSS-compliant bank web application. By using Azure’s robust infrastructure and best practices, you can focus on delivering value to your users while safeguarding sensitive financial data.
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