The explosive growth of containers is not surprising – technologies such as Docker address several problems facing developers when they deploy applications. Developers need simple packaging, rapid deployment, reduced environmental dependancies, support for micro-services, and horizontal scalability – all of which containers provide, making them very compelling. Yet this generic model of packaged services, where the environment is designed to treat each container as a “unit of service” sharply reduces transparency and auditability (by design) and gives security pros nightmares. We run more code and run it faster, begging the question, “How can you introduce security without losing the benefits of containers?”

IT and Security teams lack visibility into containers, and have trouble validating them – both before placing them into production, and once they are running in production. Their peers on the development team are often disinterested in security, and cannot be bothered with providing reports and metrics. This is essentially the same problem we have for application security in general: the people responsible for the code are not incentivized to make security their problem, and the people who want to know what’s going on lack visibility.

In this research we will delve into container technology, its unique value proposition, and how it fits into the application development and management processes. We will offer advice on how to build security into the container build process, how to validate and manage container inventories, and how to protect the container run-time environment. We will discuss applicability, both for pre-deployment testing and run-time security.

Our hypothesis is that containers are scaring the hell out of security pros because of their lack of transparency. The burden of securing containers falls across development, operations, and security teams; but not of these audiences are sure how to tackle the problem. This research is intended to aid security practitioners and IT operations teams in selecting tools and approaches for container security. We are not diving into how to secure apps in containers here – instead we are limiting ouselves to build, container management, deployment, and runtime security for the container environment. We will focus on Docker security as the dominant container model today, but will comment on other options as appropriate – particularly Google and Amazon services. We will not go into detail on the Docker platform’s native security offerings, but will mention them as part of an overall strategy. Our working title is “Assembling a Container Security Program”, but that is open for review.

Our outline for this series is:

  • Threats and Concerns: We will outline why container security is difficult, with a dive into the concerns of malicious containers, trust between containers and the runtime environment, container mismanagement, and hacking the build environment. We will discuss the areas of responsibility for Security, Development, and Operations.
  • Securing the Build: This post will cover the security of the build environment, where code is assembled and containers are constructed. We will consider vetting the contents of the container, as well as how to validate supporting code libraries. We will also discuss credential management for build servers to help protect against container tampering, code insertion and misuse through assessment tools, build tool configuration, and identity management. We will offer suggestions for Continuous Integration and DevOps environments.
  • Validating the Container: Here we will discuss methods of container management and selection, as well as ways to ensure selection of the correct containers for placement into the environment. We will discuss approaches for container validation and management, as well as good practices for response when vulnerabilities are found.
  • Protect the Runtime Environment: This post will cover protecting the runtime environment from malicious containers. We will discuss the basics of host OS security and container engine security. This topic could encompass an entire research paper itself, so we will only explore the basics, with pointers to container engine and OS platform security controls. And we will discuss use of identity management in cloud environments to restrict container permissions at runtime.
  • Monitoring and Auditing: Here we will discuss the need to verify that containers are behaving as intended; we will break out use of logging, real-time monitoring, and activity auditing for container environments. We will also discuss verification of code behavior – through both sandboxing and API monitoring.

Containers are not really new, but container security is still immature. So we are in full research mode with this project, and as always we use an open research model. The community helps make these research papers better – by both questioning our findings and sharing your experiences. We want to hear your questions, concerns, and experiences. Please reach out to us via email or leave comments.

Our next post will address concerns we hear from security and IT folks.