How Docker Hardened Images Can Help Organizations Simplify Cloud Security Practices
Many small businesses and organizations use cloud tools to avoid the expenses involved in maintaining on-site IT infrastructure. This method also allows businesses to worry less about concerns like scaling storage space or installing applications, but not even cloud computing is safe from the dangers of cybercrime. Implementing cloud security practices can be challenging for organizations without deep security expertise; however, this is where Docker hardened images (DHIs) come in.
DHIs are a component of secure-by-default development practices that come with the added benefit of requiring less in-depth technical knowledge of DevSecOps and other large-scale security practices. Understanding what DHIs are, how they work, and their role may support small businesses and organizations in establishing baseline security measures without spending time or money implementing more rigorous practices.
Defining DHIs and Containers
To really understand what DHIs are, one first has to know a little about Docker. Docker is currently the most widely used containerization tool, and with a market share of 82.84%, the brand has become synonymous with containerization technology. There are alternative services that specialize in areas like compliance and remediation, but Docker is a prominent name in the space.
DHIs are just another name for secure container images, a kind of template organizations use to make secure copies of a container. These images hold an application’s source code and all the tools, dependencies, and libraries an application’s code needs to run as a container.
DHIs are made up of layers, with each layer corresponding to a version of the image. Rather than removing layers, when a developer changes an image, they add a new layer on top. The top layer is the current version of the image, while the previous layers stay in place for rollbacks or for use in other projects.
Containers, meanwhile, are live versions of images. Their contents, unlike those found in images, are executable and can be interacted with. Since containers allow code to run in any computing environment, they make it easier to distribute and manage apps across different environments. For example, retailers sometimes use containers to track inventory in real time and deliver personalized shopping experiences via microservices.
Image Hardening and Its Uses
The “hardened” component of DHIs refers to the practice of simplifying images to reduce their exposure to vulnerabilities. If these vulnerabilities, often called CVEs (Common Vulnerabilities and Exposures), are not quickly fixed, they could leave images vulnerable to security breaches. These breaches could result in rule violations, service outages, or unauthorized access.
DevSecOps teams sometimes opt to secure container images after selecting and implementing them, but this approach can leave images vulnerable to CVEs. To minimize the risk of this happening, teams may choose pre-hardened images from containerization services that have already secured their images. DHIs are typically smaller than traditional images, which may limit the number of potential vulnerabilities for attackers to exploit.
Additionally, reputable DHI providers also continuously update their images to protect them against known vulnerabilities. This practice can reduce the need for manual patching, thereby cutting down on the dev team’s manpower required to constantly check for and implement patches.
With fewer resources spent on operations like checking for patches, dev teams can instead focus on proactive security methods like routine image scanning via automated image scanning tools. By scanning and monitoring for vulnerabilities, dev teams can detect security issues before they impact production. Reallocated resources may also be used to support onboarding efforts.
DHIs as Part of Secure-by-Default Practices
DHIs are one part of a security framework known as secure-by-default practices, effectively an operational principle that states that safe configuration should be the baseline for security. In this context, the safest configuration is thought to be one with the most restrictive, least privileged, and safest settings by default.
DHIs align with secure-by-default practices by coming pre-made with the smallest possible image sizes and the least permissions structure, which makes it so that the only people who can make changes to an image are those with the official authority to do so. While these settings may appear excessive, purposefully restrictive yet reversible defaults can simplify the process of adopting a DHI since dev teams don’t have to spend time implementing the least permissions themselves.
For an example of why this matters, picture a startup wanting to release its app to market as soon as possible without compromising security. They could choose to go with a traditional container image for their development process, but their security team would have to manually go through the image’s settings to ensure only the intended team members can access it.
If they forget a setting or overlook a specific permission, they might accidentally allow attackers to view the image. To lower the chances of missing something like this, the startup could choose a DHI with the simplest permissions structure. If the security oversight requirements are relaxed, the security team may have more time to find problems, and the development team may have more time to launch the app.
Helping Organizations Focus On What Matters Most
Although DHIs are by no means foolproof, as they still require active monitoring and routine updates, they can provide a foundation for security operations.
In reducing the complexity and rigor involved in securing traditional container images, proper DHI implementation may allow small businesses to operate with fewer resources. When paired with broader secure-by-default development practices, DHIs can be part of maintaining operational security so small businesses and organizations can focus less on maintaining security and more on doing what matters most.
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