Designing Secure Microservices Architectures in AWS

Welcome to the sixth chapter, which also kicks off the second part of our extensive guide to AWS security, titled Architecting and Deploying Secure AWS Environments. This part aims to deepen your expertise in designing secure AWS infrastructures, focusing on advanced subjects such as microservices, serverless computing, multi-tenancy, and infrastructure as code (IaC).

This new chapter focuses on the microservices architectural style, which is increasingly becoming the go-to approach for modern software development. We will initiate our discussion by examining why microservices are gaining such traction, and to offer a well-rounded view, we will juxtapose them with traditional monolithic architectures, dissecting the pros and cons of each. As we progress, the chapter will pivot to the specialized security challenges that microservices present. We will explore the shifts in complexity and responsibilities that come with adopting...

Why choose microservices today?

In the ever-evolving landscape of software development, the architecture you choose can make or break your application. The decision between a monolithic and a microservices architecture is more than just a technical choice; it is a strategic one that impacts everything from development speed to operational efficiency. This section aims to shed light on why microservices have become the architecture of choice for many organizations, especially those looking to scale efficiently and securely.

The monolithic way

Before we venture into the transformative world of microservices, it is crucial to have a solid grasp of monolithic architecture. This architectural style has been the bedrock of software development for decades. It offers a straightforward approach where all the code necessary for an application is deployed and executed from a single computing platform. This platform often includes the operating system, the database, and other software stacks...

Security considerations in microservices architectures

This section aims to provide a comprehensive understanding of the security implications that come with adopting a microservices approach. We will delve into the complexities introduced by this architectural style, the shift in responsibility domains, especially in cloud environments such as AWS, and the paradox of lightweight components that offer both security benefits and challenges.

Complexity paradigm

In the realm of software architecture, the transition from monolithic to microservices-based systems is akin to a short-term rental company remodeling its single-room studios into multi-room apartments. Imagine a studio with four corners designated for different functionalities: a workout corner, a sleeping area, a storage space, and a workspace area, as shown in Figure 6.6. Initially, the studio was simple to manage, with just one door as the entry point and a few windows for natural light. However, to adapt to market demands...

Securing communication between services

Unlike monolithic architectures, where components often reside in the same memory space, microservices communicate over a network, which exposes them to a variety of security risks. Their distributed nature introduces multiple points of interaction, each of which could be a potential security vulnerability. This section aims to provide a deep dive into implementing secure communication methods between microservices.

Zero trust principle

The zero trust model is founded on the principle of never trust, always verify, which is especially crucial in microservices architecture. In such an environment, each microservice operates in its own isolated container or virtual machine and often interacts with multiple other services. This distributed nature makes it imperative to ensure that every service is authenticated and authorized before it can communicate with another service.

In the AWS ecosystem, several services and features can be employed...

Implementing fine-grained access control

The decentralized nature of microservices demands a nuanced approach to access control. This section aims to guide you through the advanced techniques and AWS services that can help you achieve a high level of access control.

IAM as the backbone

While the foundational role of IAM in AWS security was extensively covered in Chapter 3, its specialized application in a microservices framework deserves a deeper look. Given the distributed and often complex nature of microservices, IAM offers a set of tools that enable the creation of secure, scalable, and finely tuned access control architecture.

Role-based access

In a microservices setup, each service typically performs specialized tasks and requires access to specific AWS resources. By crafting IAM roles with permissions tailored to the unique needs of each microservice, you can adhere to the principle of least privilege. Importantly, long-term credentials such as IAM user access keys...

Summary

In this comprehensive chapter, we delved into the world of microservices, starting with a critical evaluation of why they are increasingly becoming the architecture of choice. We contrasted the monolithic and microservices approaches, weighing their respective pros and cons, and provided use cases to help you make an informed decision. The chapter then transitioned into the complex landscape of security considerations unique to microservices. We discussed the paradigm shift in complexity and responsibilities, emphasizing the need for a new approach to access control and security measures. We also explored the zero trust principle and the importance of encryption, along with the types of communication—synchronous and asynchronous. AWS App Mesh and Amazon API Gateway were introduced as essential tools for managing and securing service-to-service communication. The latter part of the chapter focused on implementing fine-grained access control, highlighting the role of IAM...

Questions

Answer the following questions to test your knowledge of this chapter:

1. What are the security implications of complexity in a microservices architecture?
2. How does the lightweight nature of microservices affect security?
3. What are identity tokens, and how are they used?
4. How do IAM, Cognito, and Verified Permissions work together?

Answers

Here are the answers to this chapter’s questions:

1. The complexity increases the attack surface. Each service, its communication channel, and even the orchestrator can be potential points of failure or exploitation. Therefore, each element needs to be individually secured, requiring sophisticated access control mechanisms.
2. Each individual microservice is a lightweight component with a minimal attack surface, thanks to its simplicity. With fewer lines of code and fewer dependencies, the attack surface for each individual microservice is reduced. Additionally, the ephemeral nature of containers means that even if a container is compromised, it is less likely to be a persistent threat.
3. Identity tokens, commonly in the form of JWT, securely represent user information between multiple parties. In a microservices architecture, these tokens are crucial for securely propagating identity and claims between downstream services, aiding in both auditing and fine-grained...

Further reading

The following resources offer further insights and best practices for VPC security:

• AWS Whitepaper – Implementing Microservices on AWS: https://docs.aws.amazon.com/pdfs/whitepapers/latest/microservices-on-aws/microservices-on-aws.pdf
• Security and Microservice Architecture on AWS by Gaurav Raje (2021). O’Reilly Media, ISBN 1098101464.
• 8 fundamental microservices security best practices by Joydip Kanjilal (2021): https://www.techtarget.com/searchapparchitecture/tip/4-fundamental-microservices-security-best-practices