Container Security Tools Breakdown
Container security was initially a big obstacle to many organizations in
adopting Docker. However, that has changed over the past year, as many
open source projects, startups, cloud vendors, and even Docker itself
have stepped up to the challenge by creating new solutions for hardening
Docker environments. Today, there is a wide range of security tools that
cater to every aspect of the container lifecycle. Docker security tools
fall into these categories:
- Kernel security tools: These tools have their origins in the
work of the open source Linux community. They have been inherited by
container systems like Docker as foundational security tools at the
- Image scanning tools: Docker Hub is the most popular container
registry, but there are many others, too. Most registries now have
solutions for scanning container images for known vulnerabilities.
- Orchestration security tools: Kubernetes and Docker Swarm are
the two most popular orchestrators, and their security features have
been gaining strength over the past year.
- Network security tools: In a distributed system powered by
containers, the network is more important than ever. Policy-based
network security is gaining prominence over perimeter-based
- Security benchmark tools: The Center for Internet Security (CIS)
has provided guidelines for container security, which have been
adopted by Docker Bench and similar benchmark security tools.
- Security with CaaS platforms: AWS ECS, GKE and other CaaS
platforms build on the security features of their parent IaaS
platform, and then add container-specific features or borrow
security features from Docker or Kubernetes.
- Purpose-built container security tools: This is the most
advanced option for container security. In it, machine learning
takes center stage as these tools look to build an intelligent
solution to container security.
Here’s a cheatsheet of Docker security tools available as of mid-2017.
It’s organized according to which part of the Docker stack the tool
What it does
Kernel security tools
Isolates neighboring processes from each other. It limits what a
container can see, and thus prevents attacks from spreading.
Limits the resources used by a container. Restricts what a container can
use, and thus prevents infected containers from hogging all resources.
Provides access control to the kernel. It enforces mandatory access
control (MAC), which controls how containers access the kernel based on
Enables access controls on processes. Can be set to enforce policies, or
merely report on policy violations.
Allows processes to interact with the kernel in a “secure” state, where
it can only make a few commands. If it goes beyond these commands, the
process is killed.
Image scanning tools
Scans images that have been downloaded from Docker Hub against a list of
Common Vulnerabilities and Exposures (CVEs).
Verifies images downloaded from third-party registries based on the
author. The author of an image can be an individual or an organization.
Powered by CoreOS Clair, this is Quay’s version of Docker Security
Scanning. It scans container images for vulnerabilities.
Part of AWS ECS, ECR encrypts images at rest in S3, and in transit over
HTTPS. It Uses AWS IAM to manage access control to the registry.
Orchestration security tools
Docker Swarm Secrets
Provides a safe way to store passwords, tokens and other confidential
data using Docker Swarm.
Secures containers and pods in a Kubernetes cluster. Provides access
control, and Linux kernel security modules like SELinux and AppArmor.
Network security tools
Secures the container network by providing policy-based security that
ensures services can access only the services and resources they need
and not more.
Enforces policy-based security for the container network, and provides a
firewall for each container rather than firewalling the entire
Integrates the security features of Project Calico and the connectivity
features of Flannel to provide a comprehensive networking solution for
Security benchmark tools
A script that checks containers in production against a list of
benchmarks created by the CIS (Center for Internet Security).
A test framework built by Chef that treats compliance and security as
code. It scans images, and has its own version of Docker Bench.
Security with CaaS platforms
Runs containers inside a virtual machine, which provides the first layer
of security. Also adds AWS security features like IAM, security groups,
and network ACLs.
Has its own Azure Container Registry for scanning images, and leverages
Azure’s default security features like IAM.
Adopts Kubernetes’ security features and adds some of its own Google
Cloud security features like IAM and RBAC.
Purpose-built container security tools
End-to-end security platform for containers. It leverages machine
learning to automatically profile applications.
End-to-end security platform for containers. It provides a mature API
that can be easily extended.
Scans container images, and enforces security policies for container
platforms. Integrates with CI/CD workflows using Jenkins.
Secures container runtimes by enforcing policies for services. It can
automatically start and stop containers based on automated whitelists.
CI/CD integrated security tool that protects against known attacks.
Container security tool that leverages machine learning to provide what
it calls “adaptive threat protection.”
A hosted security solution that scans container images and even allows
enterprises to enforce security policies on their environments.
A continuous security assessment tool that scans for vulnerabilities
against the CIS benchmark, and more.
Making Sense of the Docker Security Tool Landscape
Compare architectures, feature
sets, and usability of Kubernetes and Docker Swarm. Download the
This is truly a diverse list of Docker security tools. What becomes
clear when we view this list is that Docker security requires a
combination of many tools working together. Each tool has its own
strengths and focus areas. There are solutions available for every layer
of the container stack—kernel, registries, network, orchestration, and
CaaS platforms. And the best part is that most of these tools are great
at integrating with each other, or at least the most commonly used tools
in container workloads. By knowing each of the tools, and what makes
them unique from the others, you can ensure a bulletproof container
environment that can run production workloads at enterprise scale. That
was always the promise of Docker, and container security tools are
making that promise a reality. Twain began his career at Google,
where, among other things, he was involved in technical support for the
AdWords team. His work involved reviewing stack traces, and resolving
issues affecting both customers and the Support team, and handling
escalations. Later, he built branded social media applications, and
automation scripts to help startups better manage their marketing
operations. Today, as a technology journalist he helps IT magazines, and
startups change the way teams build and ship applications.