Security Risks to Containerized Environments

May 24, 2021

Most organizations today are on a path to modernize the way they build and deliver applications and services. The benefits of modernizing are profound. Organizations can deliver revenue-generating features faster and be more responsive to their customers. They can reduce technical debt (and the potential security vulnerabilities hidden there), as well as take advantage of cloud efficiencies. However, in this shift to containerized applications security while accountable for the security of their organization does not have ownership over these applications and security hygiene is left as an after thought.

If containerized applications are in their nature, more contained... what is the risk of no security?

Misconfigurations & Defaults

Kubernetes was designed to be easy to get up and running for lab testing purposes and more. If your organization is deploying applications to production without a uniform security approach you could be over exposing your organization.

Examples of default configurations include but are not limited to:

  • Privilege Escalation: By default a container is not allowed to access any devices on the host, but a "privileged" container is given access to all devices on the host. This allows the container nearly all the same access as processes running on the host. Containers running with the privileged flag can do almost anything a host can do, run with all capabilities and gain access to the host’s devices. This means that if an attacker breaches a container running with the privileged flag, they can wreak havoc.
  • Use Kubernetes Network Policies: Networking of Kubernetes clusters defaults to an 'allow all' rule, allowing all inbound and outbound communications. In production this greatly increases your exposure to denial of service threats. Organizations need to install a network plugin to control traffic from the application and configure policies accordingly.
  • AllowedHostPaths - This specifies a list of host paths that are allowed to be used by hostPath volumes. An empty list means there is no restriction on host paths used. There are many ways a container with unrestricted access to the host filesystem can escalate privileges, including reading data from other containers, and abusing the credentials of system services, such as Kubelet.


Default configurations and associated risk are documented by Kubernetes Pod Security Standards, review for best practice recommendations when locking down your production environment. Limiting the privileges of the containers running in your cluster and enforcing those limitations can be one of the most important protections you can implement.


Containerized applications are only as secure as the code that runs in it. Container vulnerabilities are prevalent and if security is unable to shift left and identify these vulnerabilities prior to production deployment your risk will be amplified. Of Dockers 100 latest images more than 90% of the images contain a high or critical vulnerability. 

"So why do developer use pre-built images?"

Pulling a pre-built image from a public registry like Docker Hub can be completed in seconds, where manually configuring the database adds cycle time. 

With over 149K of CVEs in 2020, the security risk is only growing and if application hygiene is left unchecked, your exposure is steep.

Embedded Malware

Embedded malware on an image can be hardcoded to download malware after image deployment. This technique typically relies on downloading a pre-build image with external calls built in or exploitation of a vulnerable image.

Container Escape

Container escape if successful can be highly detrimental to an environment. Container escape occurs when the adversary is able to leverage privilege escalation or a vulnerability to break out of the container, compromising the host and the applications running on that host. There is also potential for API exploitation taking your organization offline. 



So while Containers are more contained, as with all other infrastructure, practicing good hygiene and security practices are critical in the success of your organizations security posture.

Learn how CBC Container can help you mitigate risk today!



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Sanara Marsh

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Manager, Technical Marketing, Security Business Unit, VMware. Having worked with customers at a variety of organizational levels; Sanara Marsh brings a real-world perspective on security. Taking this knowledge to TechZone, Sanara creates content focused on enabling cyber professionals to implement and optimize their security stack. "Cybersecurity has evolved to play a role in all areas of business and must be approached with a team sport mentality."