Image: Source.Migrating monolithic applications to microservices architectures has gone mainstream. Breaking systems into independent components that communicate via APIs unlocks serious agility, empowering teams to scale, upgrade, rearchitect, and innovate faster.
But with all these great benefits comes a severe downside - microservices can massively expand your attack surface. Instead of securing a single monolith, you're now fortifying a complex web of containerized services, serverless functions, distributed networks, and APIs. It's a lot to lock down.
So, how do savvy engineering teams conquer microservices sprawl? This guide explores a layered, defense-in-depth approach to securing every facet of modern, distributed architectures. We will cover comprehensive security checklists for containers, communications, identities, infrastructure, and overall governance - so use this guide to inform microservices security planning and solution architecture. Let’s dive in.
Secure Your Containers
Containers package software code and dependencies into standardized units for consistent deployment across environments. As microservices architectures rely on containers to provide portability and availability for distributed services, securing containers is paramount. Unpatched vulnerabilities or misconfigured policies in container images can provide attackers with initial access to exploit your applications or infrastructure.
By scanning images, hardening hosts, and protecting secrets, you reduce the risks associated with this foundational microservices building block. Taking an in-depth defense approach to container security serves as a critical first line of defense for your services.
Scan container images for malware: Continuously scan for malware, embedded secrets, and other risks at each stage of the container lifecycle - including the CI/CD pipeline, runtime production, and during updates—remediate findings before deployment. Be sure to scan public and private container registries for the latest CVEs.
Leverage container security tools: Linux security modules like AppArmor, Seccomp, and SELinux restrict containers' system access and defend against attacks. Use container auditing tools to validate configurations that meet security standards. Monitoring tools can detect anomalous container behavior at runtime indicative of compromises. Consider enabling Linux user namespace remapping for additional separation between containers and host.
Encrypt secrets and configs: Don't bake secrets like passwords and keys directly into container images or source code. Instead, inject credentials at runtime from external secrets repositories—Encrypt configuration files via trusted encryption technologies, stored separately from container runtimes. For production, leverage hardware-based security modules to store secrets and configs.
Isolate containers and limit resources: Strategically segregate containers based on sensitivity, hardening groups of high-risk workloads—set CPU and memory limits on containers using namespace resource quotas to prevent denial-of-service from resource exhaustion. Validate network traffic flows between containers and restrict connectivity. Make containers read-only wherever feasible to prevent malicious writes.
Protect Service Communications
Microservices are constantly chatting with each other through internal APIs and messaging systems. These communication channels between services must be locked down tight:
Encrypt everything: Encrypt all network traffic flowing between services with TLS certificates. Also, encrypt any data that touches disks or caches. To prevent spoofing, require two-way SSL authentication for service calls. And don't forget to rotate encryption keys regularly based on your security policy!
Validate all requests: Use tokens like OAuth and JWT to authenticate requests between services. Carefully scope token permissions only to what is necessary. Set short token expiration times according to your risk tolerance. And be ready to revoke tokens the moment a user is compromised.
Inspect all traffic: Implement tools that proxy service communication to enforce security policies, gather performance metrics, test resilience, and redirect failed requests. Feed logs from these tools into your security analytics to detect anomalies.
Harden messaging systems: Tightly protect your messaging systems, such as Kafka, RabbitMQ, Redis, etc., with firewalls, protocol restrictions, auditing, encryption, and backups. Isolate these systems from other infrastructure for an added layer of security.
Institute Identity Standards
With so many different services talking to each other, locking down user identities and access is crucial for microservices.
Centralize user management: Implement single sign-on by connecting all your services to centralized directories like Active Directory, LDAP, or a cloud user store. Enforce least-privilege roles and access levels across the board.
Automate access controls: With lifecycle management tools, automatically provision and de-provision user access across all systems. This prevents orphaned credentials that hackers love to exploit. Integrate with HR systems to instantly disable ex-employees.
Lock down credentials: Mandate super-complex passwords and frequent rotation for service accounts. Even better - ditch passwords entirely and use short-lived access tokens or public-key authentication instead. Enable multi-factor authentication (MFA) for production access.
Secure the Infrastructure
While microservices distribute processes across environments, the underlying cloud infrastructure still centralizes key components that, if compromised, can provide attackers with vital footholds: servers, control planes, codecs, data stores, etc.
Harden servers and networks: Production servers should be accessible only via VPN to trusted users, with locked-down firewall rules. Test and staging environments should model production as closely as possible. Automate the config of security groups, NACLs, and other networking policies.
Monitor all traffic: Inspect east-west traffic between VPCs/subnets and north-south traffic on all ports. Feed logs into analytics tools to surface trends. Implement SIEM systems to correlate events across systems. Use findings to trigger security alerts and runbooks.
Tightly control identities: Strictly limit IAM roles and permissions, revoking more than is essential. Automatically rotate IAM credentials regularly. Continuously report on and remove stale roles and overprovisioned access.
Protect data stores: Apply defenses in layers to data stores like caches, databases, and object stores - encrypted storage, backups, SSL connections, firewall rules, role segregation, scans, high availability configurations, etc.
Adopt Security Best Practices
Beyond just technical controls, you need to embed security into your organizational culture:
Test continuously: Bake rigorous security testing into your development lifecycle via SAST, DAST, pen testing, bug bounties, and red/blue teams. Make it automatic wherever possible—funnel findings into prioritized backlogs.
Document everything: Comprehensively document security policies, data classifications, regulations, incident response—you name it. Update documents annually or upon major app/infrastructure changes.
Build awareness: Establish security training for all employees. Communicate microservice risks clearly to instill shared responsibility. Make training part of developer onboarding.
Monitor analytics: Collect security telemetry across your entire microservices environment. Watch for unusual spikes in failed logins, traffic, resource usage, deployments, etc. Visualize trends through dashboards and alerts.
Update constantly: Relentlessly patch infrastructure, update service libraries, and refresh container images with the latest security fixes. Bake security scans into your CI/CD pipeline.
Final Word
While microservices introduce daunting security complexity, a layered, defense-in-depth approach allows you to manage the risk. Between perpetual scanning, traffic inspection, encryption, access controls and cultural commitment to security - you can release innovative applications built on microservices without compromising safety.
