Common Container Security Issues: Risks and Best Practices

Written by
Russ Andersson
Published on
July 13, 2023

Containers have taken the development world by storm. They’re cheap, portable, scalable, and efficient. They’ve paved the transition away from monolithic applications and helped the tech world adapt microservices that can be deployed anywhere in the world. 

In fact, they’ve become so popular that 90% of global organizations will run containerized apps in production by 2026. The same study also predicts that 20% of all enterprise applications will run in containers.

As a result, containers have become a lucrative target for cybercriminals who seek to infiltrate containerized environments and carry out various malicious actions. Attacks against container infrastructure have increased over the past two years in both frequency and sophistication. Does this mean containers are less secure and require more work? Let’s take a look.

Are containers less secure?

Compared to other virtualized technologies, such as virtual machines, container technology can be considered less secure in some aspects because:

  • Containers are mainly built using open-source components, which increase the likelihood of container security vulnerabilities.
  • Containers share the same kernel with the host operating system, increasing attack surface. Adversaries can access the host operating system or move between containers if they exploit a weakness in a container running on the same host as other containers.
  • Container technology is complex, and container hardening requires significant expertise. RapidFort makes it easy to harden your containers automatically and outsource the hassle of container security management to a trusted third-party provider.
  • In a microservice architecture, containerized apps may need to connect with other containers or resources on other devices. These connections are vulnerable to security risks like a man-in-the-middle attack. Security teams need to ensure that these connections are secured properly (i.e., using SSL).

Why is container security important?

The adoption of containers has made them a critical part of production infrastructure. Containers process sensitive information, such as personally identifiable information (PII), patient health information, and financial data. If these containers are not adequately secured, it can lead to a data breach, which could result in significant fines and penalties. 

Plus, Disruption to container applications could result in service disruptions and financial losses for your business. It's essential to have a solid container security strategy to ensure your applications run smoothly.

Container security concerns

One container in your production infrastructure can be exploited as an entry point into your entire IT ecosystem. Let’s review the most common security issues your organization will face when using containerized applications:

Base image security vulnerabilities

Container base images commonly contain insecure components or dependencies. If developers use a vulnerable base image to create their containers, the same vulnerabilities will live in their applications. Most container image vulnerabilities can be easily detected using a reliable container image scanner such as RapidFort’s free container registry SCA scanner.

Inadequate host security

If the host operating system is inadequately secured due to security vulnerabilities, such as an unpatched system, threat actors could gain access to all containers running on the host.

Vulnerabilities in container runtimes

Container runtime security means using processes and tools to protect containers from security risks and vulnerabilities when moving them to the production environment. Numerous risks can emerge once the container is running. The most common are:

  • Security vulnerabilities in container orchestration systems, such as Kubernetes or Openshift, can exploit application code in runtime to gain unauthorized access to sensitive container data. Vulnerabilities can also allow an attacker to modify container configurations at runtime.
  • Unauthorized access due to unnecessary privileges. Developers may give more resources on the host device more access than necessary. This kind of access can be exploited by attackers to gain unauthorized access. 
  • Malicious insiders who have legitimate access to the container production environment maliciously steal sensitive data.
  • Weak access security controls can allow threat actors to access running containers and steal/modify their data.
  • Inherited vulnerabilities from the container base image can allow threat actors to access container data, execute malicious code, and even compromise the underlying host operating system.   

Insufficient network security

Containers are only as secure as the underlying network infrastructure they are running on. The following network security issues significantly impact container security:

  • Networks infected with malware may infect containers running within them.
  •  Weak network security controls will allow unauthorized access to containers, which can lead to data theft.
  • A distributed denial of service attack (DDoS) will make containerized applications unavailable to legitimate users.

Weak authentication and authorization

Failure to deploy a centralized solution, such as Identity Access Management (IAM) software, to govern access to protected resources will inevitably expose containerized applications to unauthorized access.

Unsecured APIs

APIs are used extensively in containerized environments to facilitate communications between containers and other resources (services or other applications). Insecure APIs can make communications susceptible to interception, impacting the security of the entire IT environment.

Lack of visibility

Containers rely heavily on many components to perform optimally. For example, a typical GitHub project contains around 700 open-source dependencies. However, keeping track of all these components can be pretty challenging, especially when identifying potential vulnerabilities that could arise.

(Related: Check out how we “eat our own dog food” by securing our own base images for product development.)

Container security consequences

Because containers are a key element in software application development, failing to secure them properly will allow threat actors to steal data, launch DDoS attacks, or even take over your entire IT infrastructure.

  • Risk of data breaches: Containers may process sensitive information, such as PII, intellectual property, and customers' financial information, such as credit card and banking information. If the container gets compromised, attackers can access this information.
  • At-risk compliance: The information containers process could be subject to different data privacy and protection laws such as HIPAA and GDPR. Failure to protect this information will lead to varying financial and legal penalties.
  • Operational disruption: Compromised containers may require offline remediation, resulting in application or service downtime. This can damage the business's reputation and cause customer dissatisfaction, especially if the affected application or service is critical.

Inadequate container security can severely affect an organization's reputation and financial status. Therefore, addressing container security should be a top priority for any organization that wants to survive today's complex IT threat landscape and mitigate its risk.   

Best practices for container security

The best practices for achieving container security can be summarized:

Secure the container image

Following a shift left strategy will help handle most security aspects of containers early in the development lifecycle. (Important note: Shift-left on its own is not sufficient if your teams don’t have the tools to automatically remediate vulnerabilities.) Here are the most important practices to secure your containers:

  • Download container base images from trusted sources only – for example, Docker Hub is the world's most extensive library and community for container images. Downloading clean images from trusted sources allows developers to mitigate many Docker container security concerns. We also offer our own free library of hardened community images that are updated daily.
  • Remove unnecessary software packages and dependencies from container base images – RapidFort's Software Attack Surface Management (SASM) platform automatically removes components from your containers that you don't need, which efficiently improves your organization's vulnerability management task
  • Always scan container images for security vulnerabilities. RapidFort’s Free SCA Scanner can automate your container security with one simple command.
  •  Enforce strict security controls to govern who can modify and access the base image.

Secure the container host

Here are the most important measures to secure the container host:

  • Keep the host operating system up to date and patched with the latest security updates.
  • Implement security controls to restrict who can access the host operating system.
  • Install security solutions, such as anti-malware, firewalls, and Intrusion Detection Systems (IDS) to protect the host operating system from malware and unauthorized access.

Implementing security best practices such as using strong passwords, two-factor authentication, security monitoring, and logging tools can also help detect and prevent potential security breaches.

Secure the container runtime

Protecting containers at runtime was traditionally the job of security teams; however, as software development methodologies continue to advance, securing containers at runtime has become the development team's responsibility. This Shift Left practice requires incorporating security into the early phase of the SDLC.

Secure the container network

There are some important ways to enhance container network security:

  • Isolate sensitive containers in the most secure network segments.
  • Use encrypted communications channels between containers and other applications or services within your network.
  •  Leverage security tools, such as next-generation firewall (NGFW) and IDS/IPS (Intrusion Prevention System), to detect abnormal network activities that may impact container security.
  •  Apply the principle of least privilege, which entitles every user should be given the access privilege required to perform the job at hand and nothing more.  

Implement strong authentication and authorization

A strong Identity and Access Management (IAM) solution is the best method to regulate access to protected resources. Note that access to protected resources is not limited to users or humans. Applications, services, and other systems may also require access and should be governed by IAM according to their job duties.

Secure the container API

Some of the best ways to enhance container API security include:

  • Enforcing proper authentication mechanisms to identify API clients and restrict access to authorized users and applications.
  • Using HTTPS to protect communications between the API and its clients. If you want to make your Docker daemon socket reachable via HTTP, use TLS (HTTPS) to protect it.
  • Monitoring network traffic to identify anomalous communications.

Ensure visibility of components and dependencies

Containers are composed of many open-source and/or third-party provider dependencies. For complete visibility over all components and dependencies in your container, it is critical to create a software bill of materials (SBOM)

An SBOM is a record of all software components (e.g. code libraries and modules) that comprise software applications. It should list every container component and provide information such as:

  • Component information (name, version, license).
  • Vendor information (name, contact).
  • Transitive dependencies.
  • Security vulnerabilities associated with each component and mitigation. 
  • Strategies to resolve listed issues.

 RapidFort's Software Attack Surface Management (SASM) platform automatically generates SBOM records for your application, providing an extensive list of all software components used in your container.

New technology, new security challenges

Containers are a powerful technology that can help you deploy and manage applications quickly and easily. However, they also introduce new security challenges. Inadequate container security will turn those advantages into a nightmare for your business's finances and reputation.

Container security is essential to protect containers from security risks and vulnerabilities throughout the CI/CD pipeline, deployment infrastructure, and supply chain.

RapidFort Community Container images on Github provides a rich library of the most popular container images on Docker Hub. We optimize and harden them every day, and they are available to anyone for free. Check out the free resource to bolster your container security.

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