Five things you need to know about Linux container security

As cloud adoption soars, containers are gaining more popularity, too. Linux Containers (LXC) lead this segment, accounting for 33.5 percent of the containerization market as of 2021. This popularity makes it a tempting option for developers, but it is important to consider its security, too.

Containers are sets of one or more processes that are isolated from the rest of the system. This allows the application to run quickly and reliably between computing environments. Containers enable infrastructures to run more productively, efficiently and cost-effectively, which is why they have become so popular.

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Linux containers have several security advantages, listed below, but reliable cyber security does not come without user action. Developers must understand LXC’s security benefits and risks to make the most of what is available and minimize vulnerabilities. When they know more about how to secure these systems, they can create safer environments.

With that in mind, here are five things you need to know about Linux container security.

Linux containers make it easy to isolate breaches

Generally speaking, containers make it easier to ensure cybersecurity for the apps they host. Their organization provides more visibility into overall workflows and connections. Just as data visualization improves comprehension and accelerates decision-making, visualization through containers can help understand and respond to breaches faster.

Linux security takes the cyber security advantages of containers further. Since LXC hosts the system’s kernel directly, it is easier to isolate sensitive services. If you discover a breach, you can separate the compromised container from the rest of the network with minimal disruption, containing it before it causes further damage.

Not all containers are equally safe

While Linux containers have some security advantages, it’s important to remember that they’re not necessarily safe by design. LXC comes in two main forms, privileged and unprivileged, with the latter offering more security. If developers do not understand these differences, they may think they are more secure than they actually are.

Privileged container’s unique identifier (UID) 0, which bypasses security checks, maps to the host’s uid 0. That opens the door to exploits that give attackers full host privileges if they breach the container. Unprivileged containers, by contrast, map the container UID 0 to an outside, unprivileged user, preventing these attacks.

Container content can be a threat

One of the development advantages of using Linux containers is the availability of ready-made containerized open-source packages. Users can download apps and infrastructure in LXC to integrate into their container environments with minimal effort. However, this also presents a security threat, as attackers could easily list malicious or infected containers on public registries.

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Developers must ensure they know where their downloaded containers are coming from. Only use containerized packages from trusted sources on trusted libraries. Even then, it’s best to inspect container content to ensure it contains no malicious code before deploying it.

SELinux can improve container security

There are a few Linux security tools that developers should use to bolster their containers’ safety. One of the most important of these is SELinux. SELinux, short for security-enhanced Linux, comes from the National Security Agency (NSA) and makes it easier to restrict system access.

With SELinux, administrators can define security policies that restrict what each container or app can access. When something requests to access an object, SELinux will check these rules before denying or accepting the request. If there are no specific policies about it, it will check the app’s security context to see if it should accept or deny it.

Linux’s ease of use can be a security asset

While technical security controls like SELinux are crucial, some seemingly unrelated factors can affect Linux security. Since 85 percent of data breaches involve a human element, preventing user error is a critical security step. Consequently, Linux containers’ ease of use is valuable for cybersecurity.

LXC is fairly easy to use, thanks to its simplicity and visibility. Linux’s popularity as an operating system also means there are plenty of resources to help developers understand their container environments. As a result, using these containers may help make them more secure than other, less user-friendly container platforms.