What Is Container Security? Definition, Components, Best Practices, and Software

Container security is defined as a set of tools, policies, and processes designed to enhance the security capabilities of a container so that the applications it houses can run without any security incidents or vulnerabilities arising from misconfigurations. Given that nearly a third of all organizations containerize over 50% of their applications, enterprises cannot afford to ignore its security aspect. This article discusses the definition of container security, its Linux-specific issues, tips, and software recommendations. 

Table of Contents

• • What Is Container Security?
  • Key Components for Secure Linux Containers
  • Top 9 Best Practices for Container Security
  • Top 5 Software Solutions for Container Security

What Is Container Security?

Container security is a set of tools, policies, and processes designed to enhance the security capabilities of a container so that the applications it houses can run without any security incidents or vulnerabilities arising from misconfigurations. 

A container is a self-sustaining, independent software unit that packs up its entire internal code. Containers are extremely important in digital transformation. They allow developers to create isolated environments to run and test applications in a predictable space, separated from other infrastructure applications. Containers are also easy to port, making it possible to test performance in virtually any environment that the developer wants. 

A surveyOpens a new window asked organizations what percentage of their apps were containerized. In fall 2018, 13% said over half of their applications used container technology. In 2020, this number stood at 29%, and it’s constantly growing. Cloud-based container technology like Kubernetes has been integral to the technology’s popularity, empowering developers with production-grade tools. But all of these benefits are subject to security concerns. 

ResearchOpens a new window suggests that a sizable 45% of organizations have delayed or slowed down application deployment due to security challenges. This could slow down your digital transformation journey as a whole, increasing the time-to-value from your digital investments. This is why container security emerged as a top priority in the last couple of years. 

However, before organizations can invest in container security, they must remember a vital fact: containers are more secure than traditional run-time environments by nature. Because they isolate applications from the surrounding environment, it is easier to spot the root cause of vulnerabilities and ensure safer software patching. 

This doesn’t mean that containers are inherently 100% secure. You need to carefully assess the existing security functionalities of your container platform before you get started. Some key elements of a container security plan include: 

• • Compliance checks feature 
  • Ability to create an infrastructure that is easy to audit 
  • Vulnerability management to prevent security incidents
  • Run-time threat detection to build safer applications within containers 
  • Risk profiling and assessment to strengthen application security
  • Configuration management to fine-tune application performance inside the container 

Notably, the risks surrounding container security aren’t the same as a traditional, networked environment. For instance, a traditional data breach or DDOS attack cannot penetrate a container. This is probably why the fear of attack is a less popular theme in container security (a concern for only 12%), with misconfigurations (61%) and vulnerabilities (27%) making up the lion’s share. Let us now understand container security, specifically in the context of Linux. 

Also Read: Top 10 Cloud Security Challenges 2021 Needs to Address

Key Components for Secure Linux Containers

Linux is used by almost 55%Opens a new window of developers. Container security on Linux is fundamental as Linux containers shape most enterprise apps and early-stage development efforts. Linux container security has the following components: 

1. Linux namespaces 

Namespaces is a Linux feature that partitions its resources so that one group of processes will see certain resources while a different group of processes will see different resources. Namespaces helps define the “awareness” of a process inside a Linux container, determining its performance, and preventing security vulnerabilities. 

2. Security-Enhanced Linux (SELinux) 

SELinux is a security module that defines access control policies in a Linux environment. Developed by RedHat and the NSA, SELinux is crucial for running secure Linux containers. Essentially, it prevents processes inside the container from interacting with each other or the host OS. 

3. Secure computing mode (Seccomp) 

Seccomp is a Linux feature that restricts app actions inside a container. Using Seccomp, you can prevent an app from making any system calls that might endanger security, thereby making the container secure. 

4. CGroups 

CGroups or control groups let developers isolate, restrict, and track the number of resources being consumed by processes within a container. Suppose a security flaw is leading to resource consumption beyond the expected threshold. In that case, it will be immediately visible and won’t be able to consume beyond a certain point thanks to CGroups. 

Also Read: What Is Cloud Computing? Definition, Benefits, Types, and Trends

5. Code content 

Sometimes, it is the code – and not the container – that allows vulnerabilities to creep in. Any application development exercise will rely massively on open-source code snippets, which could have inherent vulnerabilities. In a DevOps environment, where speed and rapid production is a top priority, the unbridled user of open source is fraught with risk. Therefore, secure code selection and utilization inside a container are vital for Linux container security. 

6. The container registry in use 

Developers frequently use popular container registries like RedHat Quay, Amazon ECR, Alibaba Container Registry, Docker Hub, etc., to avoid building container images from scratch. But these downloaded images must be passed through the same security policies as internally built images to eliminate leftover artifacts and keep security risks at a minimum. 

7. User privileges 

User privileges restrict containerized applications from making any modifications to their environment. It is always advisable that containers are run as users and not as root on Linux as this keeps privileges to a minimum. You can also use namespaces to create containers without root privilege. A good rule of thumb is to follow a zero-trust policy, where the container is assigned as few privileges as possible. 

8. Unikernels 

Unikernel is a new technology that makes it possible to run code directly in a bare-metal space without the need for a host or surrounding OS. Unikernels are yet to be fully mature and market-ready. However, its promise of a single-address-space machine-image that runs without an OS is too alluring to ignore. RedHat’s ongoing UKL project based on Linux could become a go-to-container security component in the future. 

These eight elements should be on every developer, DevOps team, and IT team’s radar when leveraging Linux for application development or digital transformation. The Linux OS gives you several handy tools to strengthen a container’s already-strong security posture, and advancements like Unikernels are the next step forward. 

Also Read: What Is Email Security? Definition, Benefits, Examples, and Best Practices

Top 9 Best Practices for Container Security

As developer use of containers increase, so will the potential security risks that creep into your applications. This is compounded by the fact that most containerization activities happen on the cloud, with AWS (78%), Azure (39%), and Google Cloud Platform (35%) supporting a large portion of native cloud container deployments. 

You need to follow the requisite security best practices so that the benefits of container technology do not come at a price. These include: 

1. Restrict container lifespan to shrink the attack surface 

Containers were originally meant to be temporary, not a permanent virtualized space where you can constantly add data/code, extract information, and update only occasionally every few months. Temporary containers with a very short lifespan make it almost impossible for any inherent code vulnerabilities to take root. Reduce the volume of objects inside a container and keep them brief to serve the purpose of application development enablement without letting in security flaws. 

2. Pay special attention to the containers that support your microservices 

Microservices are largely steady, ongoing processes that are scaled up or decommissioned as per business requirements. For example, an ecommerce website could run on microservices to capably cope with traffic spikes. However, microservices must function with significant network exposure, which makes them open to attacks. The underlying containers housing these microservices could also suffer. 

There are two ways to tackle this. First, have a real-time log analytics solution in place that can surface the root cause of a vulnerability before the container is automatically deleted (due to its typically short lifespan). Second, give any container housing microservices minimal user privileges so that it cannot rewrite any data even if there is a malware attack. 

3. Source your container images carefully 

Image files let you get started with container technology with minimal manual effort. But you could also be inheriting someone else’s image vulnerabilities, misconfigurations, and potentially hidden malware. That’s why a container image’s source of origin is so critical. Check the digital signature of any image you download to verify that it comes from a trusted publisher. Opt for globally recognized image registries wherever possible to minimize the risks of open source. 

Also Read: What Is Cloud Computing Security? Definition, Risks, and Security Best Practices

4. Spend time on configuring user privilege 

We can’t stress this enough — user privileges and restricted access make containers secure in the first place. You can maximize this attribute by defining “least privileges” for every container. Remember to namespace the user proactively (it is not a default setting). In that case, even if an attack penetrates the container boundary to reach the host OS, it cannot gain root-level privileges. Take time to specify roles for individual or group users instead of assigning cluster privileges in a one-size-fits-all model. 

Restricting resource utilization is also critical. An attacker might run resource-heavy processes like Bitcoin mining or torrent peers within the container, starving the other processes in your infrastructure. 

5. Leverage a host designed explicitly for container deployment 

Container security is a two-way street. Just as the container shell must be hardened to prevent any internal vulnerabilities from getting out, the host operating system must also be robust enough to withstand an attack and not let its impacts spread beyond its perimeter. 

Therefore, it is a good idea to use a very small Linux distribution when containerizing your application development process. A small number of containers run on each host, and even if a host is breached, it has no impact on other hosts or the containers running on them. 

6. Make troubleshooting accessible externally 

Whenever a developer/member of the DevOps team opens the container to configure its inner components, there is a risk of exposure. In other words, the very act of trying to strengthen container security could diminish the container’s inherent strength. 

You can limit this risk via external troubleshooting, where a developer can monitor and analyze performance records without logging in. Here’s where container security platforms will come into play, as it offers an outside-in view of container performance. You can simply deploy a new container to replace a flawed one without having to open a broken/vulnerable container at all. 

Also Read: Top 10 Cloud Computing Service Provider Companies in 2021 

7. Don’t run mission-critical processes on a container host 

When it comes to container security, it is always better to err on the side of caution. Assume that the level of isolation a container provides is always imperfect, and some porousness may remain. Working on this assumption, it’s easy to see why mission-critical processes (e.g., payroll, ecommerce websites, etc.) need their own host. Containers have their own security requirements, which will not align with the business-specific security protocols. So, it is best not to mix the two. 

8. Maintain a clutter-free container environment 

Given the ephemeral nature of containers, it is hard to conduct post-attack forensic analysis. The container automatically deletes itself, preventing a traditional root cause analysis exercise. Avoid adding to this complexity by failing to delete defunct/inactive user roles. Regularly monitor container access across its lifecycle and remove any roles that aren’t in use. This will help pin down the exact responsible user role at the time of troubleshooting or security investigation. 

9. Take advantage of real-time threat detection and response 

One of the primary reasons to run a container is to let an application play out all its potential vulnerabilities, bugs, and misconfigurations in a safe environment. But you should be able to detect it before there is any lasting damage and react with a swift response. Real-time Opens a new window threat detection alerts you about a security incident before it has reached a later stage, and the container is possibly deleted. You can link your detection mechanisms to a response system – this lets you promptly raise a ticket, notify personnel, or trigger an automated action without delays. 

These nine best practices ensure that you get the most value out of your containers and use them to safely develop and run applications. Additionally, you can also use specialized technology that is designed to reduce container security risks. 

Also Read: Top 8 Big Data Security Best Practices for 2021

Top 5 Software Solutions for Container Security 

The container security software market is growing rapidly to keep pace with the rising popularity of containers. From $568 million in 2019, it is on track to cross $2.1 billion by 2024 at a 30.9%Opens a new window compound annual growth rate (CAGR). Let us look at some of the leading names in the market (arranged in alphabetical order) and how they can aid your vision for container security. 

Disclaimer: These listings are based on publicly available information and include information from vendor websites that sell to mid-to-large enterprises. Readers are advised to conduct their own final research to ensure the best fit for their unique organizational needs.

1. Aqua 

Overview: Aqua is a cloud-native application protection solution for end-to-end application development stack. Aqua addresses security needs across virtual machines, containers, and serverless workloads. 

Features: Aqua provides the following capabilities: 

• • Specialized security for Kubernetes-based container environments 
  • Scanning of continuous integration builds and container images 
  • Dynamic container analysis to find hidden malware in open source packages
  • Aqua Risk Explorer to visualize and prioritize risks 
  • Aqua vShield to compensate for unfixable vulnerabilities using virtual patches 
  • Third-party image assurance, container immutability, and workload firewalls 

USP: Aqua’s powerful data analysis capabilities make it possible to conduct in-depth audits and send alert data directly to your SIEM systems. 

Pricing: Free for developers in non-production environments and up to $2099 per month for an enterprise-grade container security solution. 

Editorial comments: Aqua is an excellent solution for a wide range of use cases, from independent development to system integrators overseeing large-scale digital transformation. 

Also Read: Top 10 Cloud Computing Certifications and Courses in 2021

2. Docker Enterprise 

Overview: Docker is one of the world’s most popular container orchestration platforms, with robust security features. In fact, it has all the tools you’d require to develop applications in a containerized environment. 

Features: Docker Enterprise boasts of the following container security features: 

• • Granular and flexible role-based access controls to limit user access 
  • Secure application zones to create multi-tenancy within clusters 
  • Cryptographic digital signing to verify third-party images 
  • Image vulnerability scanning with automated insights 
  • Automated, policy-based image curation to maintain a safe image library 
  • Compliance with U.S. federal government standards and TLS authentication out of the box 

USP: After Linux Containers (LXC), Docker is the world’s most popular containerization software. Its comprehensive feature set — across run-time capabilities, developer tools, Kubernetes readiness, and security capabilities — makes it a one-stop-solution. 

Pricing: $7 per user per month for small-to-mid-sized teams and $84 per team seat per year for large organizations (including advanced security features). 

Editorial comments: If you are already using Docker in some capacity, we would recommend upgrading to an advanced plan that gets you audit logs, role-based access control, and unlimited image vulnerability scans. 

Also Read: What Is Application Security? Definition, Types, Testing, and Best Practices

3. NeuVector 

Overview: It is a specialized full lifecycle container security solution that integrates with popular container orchestration tools like Kubernetes and OpenShift. 

Features: Its key features are: 

• • Vulnerability scanning for the entire CI/CD pipeline 
  • Application container behavior analysis to automatically build security policies 
  • Provides security policies as code, integrating them throughout the pipeline 
  • Compatible with all major cloud platforms and SIEM systems 
  • Real-time threat identification and blocking

USP: NueVector covers the entire build-to-ship-to-run application lifecycle, integrating with all major cloud environments, virtual machines, or bare-metal hosts. It automates a large part of security policy formulation and deployment. 

Pricing: Free trial available; pricing based on host environments. 

Editorial comments: If you’re in the market for a pure-play container security solution (without developer tools, etc.), NueVector is the way to go. 

4. Snyk Container 

Overview: Snyk has several solutions for application development security. Snyk Container empowers developers to identify and troubleshoot vulnerabilities in a containerized environment. 

Features: Snyk offers the following features: 

• • Analysis of open source libraries, third-party images, newly created images, and registries
  • Tracking of vulnerability fixed rates across different teams 
  • Kubernetes workloads monitoring and misconfiguration detection 
  • Compatibility with Amazon EKS, Azure Kubernetes Service, RedHat OpenShift, and other Kubernetes-led platforms 
  • Supports major Linux-based hosts such as Ubuntu, Alpine Linux, etc. 
  • Risk dashboards to trace risk dependencies, vulnerability priorities, and open-source issues 

USP: Snyk’s USP is its robust response mechanisms. Not only can you detect the problem, but you can also resolve it using Snyk’s tools.

Pricing: Free for up to 100 container vulnerability tests; the Pro version costs $199 per month, including Jira integration, private registries, and advanced project management. 

Editorial comments: Snyk is best suited for high-growth startups that need to leverage container security as part of its application development and project management stack. 

Also Read: 4 Steps Towards Building a Hyperscale Cloud Computing Infrastructure

5. StackRox 

Overview: StackRox is a Kubernetes-native container security platform that works with a wide range of environments, including AWS, Azure, Docker, Google, etc. 

Features: StackRox’s core features include: 

• • Visibility into the full container landscape, spanning images, registries, deployments, and run-time behavior 
  • Audits against CIS benchmarks, HIPAA standards, and more via interactive dashboards 
  • Risk profiling of container deployments to prioritize remediation
  • Configuration management as per preset policies
  • Threat detection and automated incident response through built-in features or integrations 

USP: The biggest pro of StackRox is its list of integrations. It works with all major Kubernetes container platforms, image registries, image scanners, and CI/CD tools. You can also connect it to Slack, Jira, Splunk, or even email for automated workflows. 

Pricing: Pricing varies as per volume and host environment. 

Editorial comments: Companies relying on Kubernetes technology, with a sprawling digital landscape, could gain significantly from StackRox and its library of pre-built integrations. 

In a complex digital environment, one shouldn’t assume that containers are inherently secure and don’t need further protection. An increasingly large portion of our development activities are moving to containers, and vulnerabilities at this level can have a ripple effect. By following container security best practices and leveraging the right tools, you can maintain a safe CI/CD pipeline where quality, speed, and security co-exist. 

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