Over the past few years, technologies like cloud computing and microservices emerged to meet the increasing demands of scalability, resilience, and availability. Microservices architecture has been an emerging trend in software architecture over the past few years and holds many promises – faster time to market, better scalability and loosely coupled components.
However, this conglomeration of several small autonomous services modeled around a business domain using disparate technologies, tools, languages, and frameworks comes at a cost – it complicates service to service communication, handling data consistency and increases the attack surface manifold.
This article unravels some of the mysteries surrounding microservice security, talks about the challenges of securing a microservices architecture, the solutions and security best practices to adopt when building microservices-based applications.
Security Challenges in Microservices Architecture
In this section, we will examine the security challenges faced in microservices architecture.
Increased Attack Surface
The conglomeration of several services running on different ports increases the attack surface – you have several ports that are open, several APIs exposed – these all become a challenge. In a microservices-based application, each individual microservice communicates without another microservice through well-defined APIs – this increases the attack surface and makes the APIs vulnerable to security threats. To overcome this security threat, it is imperative that all microservices are properly secured.
This is one of the essential features of a microservices-based application. In a typical microservices-based application, you should be able to build, test, extend, deploy, and maintain the application in an isolated way, i.e., none of these activities should affect the functioning of any of the other microservices in the application.
You should implement isolation at the database level as well. This means that each microservice should have its copy of data and should not be able to access the data pertaining to the other microservices in the application. By implementing isolation at all layers, you can make your microservices-based application more secure.
Logging monolithic applications in the traditional way have been in use for a long time now. However, the same old traditional way of logging is ineffective in a microservices-based application. This is because in a microservices-based application you would typically have distributed, stateless, autonomous services that have been developed in heterogeneous technologies even spanning geographical distances. For logging to be effective, your application should be able to aggregate the logs and correlate the events across several services and platforms.
For microservices architecture to be successful in an organization the development and operations teams should work closely – they should be able to interact with each other as and when needed. For the success of microservices architecture in an organization, while the development and operations teams should converge, they should also have a good understanding of the processes involved and how security risks can be mitigated.
While there are benefits in building applications by developing, deploying, and managing services independent of each other, security vulnerabilities galore since the applications are released sans thorough testing. Although microservices-based applications can have frequent releases, this improved agility comes at the cost of security – since there are frequent builds the applications may not have been properly tested before being released.
Fault tolerance is the ability of an application to continue to work in the event of a failure of one or more components. It is done by implementing a fallback mechanism – the circuit breaker pattern is often used in such applications. Implementing fault tolerance in a microservices-based application is a daunting task – it is far more complex and difficult to implement than in a monolithic application. Due to the increased number of services, you have more requests and when the number of services communicating over the network increases, the complexity increases as well. Your services should be fault-tolerant, i.e., they should be able to cope up with service failures. If such service failures happen often, this can destabilize your entire application.
Best Practices to Build Secure, Scalable Microservices
Now that we know the security challenges, here’s how we can overcome them.
Defense in Depth
You may leverage the defense-in-depth strategy to protect your microservices. This approach entails adding many levels of security control to an application. Layers of security cover are used to safeguard critical services. If an attacker has successfully attacked one microservice, they may be unable to exploit another service in the application. This is because of security countermeasures applied to those services for additional security. This implies that if a prospective attacker has already attacked one layer of protection in an application, the other application layers might not be compromised easily.
In a typical microservices-based application the service consumers are not able to communicate with the microservices directly. Rather, an API Gateway is used that provides a single point of entry for directing traffic to various microservices. Hence the clients don’t have any direct access to the services and cannot exploit the services. If your API Gateway is placed behind the firewall, you can add a layer of protection around the attack surface. Once you have placed the API Gateway behind the firewall, you’ve secured all the microservices you’re using in this application. API Gateways are usually secured using token-based authentication.
Data and API Security
A typical microservices-based application requires that the services communicate with one another. This communication should be secured without affecting the application’s performance. Security certificates should be maintained and the data in transit should be encrypted and made secure.
Access to APIs must be secured – no one except the authorized users should be allowed to access them. You should take advantage of the concept of least privilege to restrict access to a resource, i.e., only give access to a resource when it is necessary.
How to Build a Microservices Security Strategy
When you are working in a microservices-based application, the usual firewall that is used to protect the organization’s data and applications running on it would not suffice. You would need to build a much more robust defense mechanism to combat security threats. In a typical monolithic application, security is an afterthought, but the same approach wouldn’t work in a microservices environment. Security for your application must be an integral part of your architecture. You should start building your security framework from the start.
Since security is an increasingly complex challenge in microservices-based applications, it is imperative that you have a security strategy in place to combat these challenges. To build a microservices-based application that is secure and scalable, the security, operations, development, testing teams should work together – it’s crucial that they collaborate with each other in a DevSecOps environment. You should also have automation in place to be able to monitor your application and the potential threats for all services that have been publicly exposed. You need a centralized security system in place together with automation – and tools such as, Prometheus, InfluxDB, etc. that can help you monitor microservices-based applications efficiently.
In a microservices security solution, you should also have automated code scanning, secure code protection and continuous updated. DevOps as well as security teams need to collaborate closely and be vigilant to prevent unauthorized or unauthenticated access to any resource within the application.
Microservices Security Tutorial
Microservices hold many promises- faster development, faster time to market, improved scalability, and loosely coupled architectures. However, despite the allure of microservices, there are many challenges and hurdles you might need to combat to be successful. The security challenge is one of them that should be dealt with not to deter the benefits of microservices.