What is Container Security?
Container security is the process of using tools and setting policies to ensure that containers are protected from threats and operate in a secure environment. Containers are a type of virtualization technology that allows applications to be packaged with their dependencies and run in isolation from other applications on a host operating system. They are commonly used in microservice design patterns and container technologies such as Docker and Kubernetes.
Ensuring the security of containers is important for protecting both the applications they support and the infrastructure they rely on. This includes protecting against threats such as malware, unauthorized access, and data breaches. It also involves ensuring that containers are built, deployed, and runtime in a secure manner.
To achieve container security, organizations can use a variety of tools and practices. This may include using container security platforms to monitor and secure container images, implementing security policies and controls, and conducting regular security assessments.
Obstacles to Ensuring the Security of Containers
Containers have become a popular choice for organizations looking to improve the efficiency and scalability of their applications. However, containers also present unique security challenges that must be addressed in order to ensure the security of containerized environments.
One major challenge is the increased attack surface created by containers. Because containers are based on a large number of different underlying images, each of which may have vulnerabilities, they can create a larger attack surface than traditional workloads. This makes it more important to ensure that container images are secure and regularly updated to reduce the risk of vulnerabilities.
Another challenge is the shared kernel architecture of containers. While securing the host system is important, it is also necessary to maintain secure configurations for containers and ensure proper isolation between containers. This can help to prevent container breaches from spreading to the host system.
Guidelines for Ensuring the Security of Containers
Container Security Images
To ensure the security of containerized environments, it is important to secure container images. This involves including the application within the container image as a statically compiled binary, removing unnecessary components, and using trustworthy images.
One way to include the application within the container image is to use a statically compiled binary. This means that the application and all of its dependencies are compiled together into a single executable file. This can help to reduce the risk of vulnerabilities being introduced through external libraries or tools.
It is also important to remove any components that the application does not need. For example, removing the “sed” and “awk” binaries that are present by default on UNIX systems can help to reduce the attack surface.
Container Security Registries
Securing container registries is an important part of ensuring the security of containerized environments. Container images are typically stored in private or public registries, and securing these registries can help to ensure that images are free of vulnerabilities.
One way to secure container registries is to use access controls. This involves defining who can access and publish images and who cannot, and can help to prevent unauthorized parties from modifying, publishing, or deleting images.
Another way to secure container registries is to sign images. Image signatures can help to track images to the individuals who signed them, making it more difficult to substitute signed images for compromised ones. Tools such as Docker Content Trust and Notary can be used to sign and verify images.
Finally, scanning images for vulnerabilities can help to identify known vulnerabilities and detect critical threats. Vulnerability scanners can be used on a continuous basis to ensure that registries do not contain critical vulnerabilities.
Container Security Deployment
To secure containerized deployments, there are several measures that can be taken. One way to secure the target environment is to harden the underlying host operating system, establish firewall and VPC rules, or create special accounts that limit access.
Using an orchestration platform can also help to secure deployments. These systems typically provide secure API endpoints and role-based access control (RBAC) to help minimize the risk of unauthorized access.
Another way to secure deployments is through the use of immutable deployments. This involves creating an instance image during the build process, and using this image to create new instances for deployment. To update the application, new images are created, new instances are spun up, and the old ones are destroyed. This can help to prevent unauthorized changes to the application and ensure that only approved updates are deployed.
Securing Container Runtime
To secure container runtime, there are several best practices that can be followed. One way to secure runtime is to create separate virtual networks for containers, which can introduce a level of isolation and reduce the attack surface.
It is also important to apply the principle of least privilege, which means allowing connectivity only between containers that truly need it. This can help to reduce the risk of unauthorized access or exploitation.
Exposing only the ports that serve the application can also help to secure runtime. This means not exposing any other ports, except for SSH, and applying this principle to containers as well as underlying machines.
Using TLS to secure communication between services can help to encrypt traffic and ensure that only authorized endpoints are allowed. This can help to protect against potential threats.
Finally, using the Docker Image policy plugin can help to prevent processes from pulling images that were not previously allow-listed. This can help to ensure that only approved images are used in the runtime environment.
Securing Kubernetes
There are several best practices that can help to secure Kubernetes environments. One way to do this is to enable TLS everywhere, which can help to defend against traffic sniffing and authenticate identities at both ends of each connection.
Using a service mesh architecture can also help to secure Kubernetes environments. Service meshes are networks of persistent encrypted connections between high-performance sidecar proxies, and they provide traffic monitoring, management, and policy enforcement without affecting microservices.
Another way to secure Kubernetes environments is to use Open Policy Agent (OPA), which enforces custom policies on a Kubernetes object without reconfiguring or recompiling the Kubernetes API server.
Applying network policies can help to restrict traffic between pods, while implementing private networks can help to secure connections to corporate networks and minimize the overall attack surface. Keeping the etcd cluster separate and using a firewall to protect it can also help to secure Kubernetes environments.
Regularly rotating encryption keys and certificates can help to minimize the blast radius of an attack that compromises keys, while using static analysis for YAML can help to identify the organization’s risk tolerance and compliance requirements.
Managing secrets through the integration of clusters using a secret management system can help to ensure that application pods automatically receive all secrets and passwords needed at runtime. Scanning code and using static analysis to ensure automation security can also help to secure Kubernetes environments.
Using RBAC policies based on the principle of least privilege and implementing centralized authentication and authorization systems like SSO can help to manage access policies and protect resources. Using third-party authorization for API servers can also help to manage and secure API access.