In today's world, securing networks from possible threats and attacks is more than a necessity; it's an absolute must. In my role as an AWS network security expert, I recently had an opportunity to work on an interesting project where the customer required a network firewall setup for an Internet Application Server.
In this case study, I will be detailing the process and decisions that went into setting up this network firewall, with an emphasis on traffic management for both incoming and outgoing connections.
Understanding the Need
The customer's main concern was to protect their application server from unauthorized access and safeguard the system from potential threats. An Internet Application Server is often a prime target for cyber-attacks, as it handles and processes a variety of sensitive user data. Therefore, it was essential to design a security strategy with multiple layers of protection.
Solution Approach: AWS Network Firewall
Our tool of choice was AWS Network Firewall, an Amazon Web Services offering that provides scalable, high-availability firewall protection for your virtual private cloud (VPC) environments.
Network Design and Firewall Placement
The customer's application was hosted in a VPC. For optimal protection, we placed the AWS Network Firewall at the VPC's ingress and egress points. This allowed us to control all incoming and outgoing traffic effectively.
Incoming Traffic Control
1. IP Allowlisting
The first rule we implemented was IP allowlisting. This rule permitted access to the application server only from a pre-defined list of IP addresses. These were trusted IP addresses of the other services the application server had to interact with.
2. Port Allowlisting
Next, we specified the port numbers that were allowed to receive incoming traffic. For example, port 80 and 443 were allowed for HTTP and HTTPS traffic, respectively.
3. Deep Packet Inspection (DPI)
DPI was used to examine the data part of a packet as it passes the inspection point. It helped detect anomalies and potential threats in incoming traffic.
Outgoing Traffic Control
1. IP Whitelisting
To ensure that the application server only interacted with trusted services, we implemented IP whitelisting for outgoing traffic.
2. Port Allowlisting
We specified the port numbers that were allowed to send outgoing traffic, ensuring that only essential connections were made.
3. Content Filtering
Content filtering rules were set up to prevent the server from sending sensitive information to unauthorized destinations.
Post-Implementation Monitoring and Alerting
After the firewall rules were implemented, it was crucial to monitor the network traffic continuously. We used AWS CloudWatch for real-time monitoring of the AWS resources and applications, and AWS CloudTrail to record and retain all API requests made by or on behalf of the AWS Network Firewall in your AWS account.
The implementation of AWS Network Firewall in this case study allowed for a robust security layer for the Internet Application Server. The detailed control of both incoming and outgoing traffic made it possible to significantly reduce the risk of unauthorized access or potential threats.
Remember that every scenario is unique, and what worked for this case may not be entirely applicable to another. As a security professional, it is essential to understand your environment, identify potential vulnerabilities, and design your firewall rules accordingly. This case study serves as an example of what you can do with AWS Network Firewall and how you can optimize it for your application server's security needs.