Kubernetes is a robust open-source platform that simplifies the management of containerized applications. Boasting portability and flexibility, the platform exhibits compatibility with various environments, including Linux, MacOS, and Windows.

‍

A prominent feature of Kubernetes is the configuration of a range of resources. These configurations dictate operational activities, the overall efficiency of the application's functioning, and the security levels of the application resources.

‍

Nonetheless, in the deployment of Kubernetes, misconfigurations are frequently encountered if guidelines are not strictly adhered to. Such misconfigurations can lead to several complications, including vulnerability to attacks and unauthorized access to sensitive data, making it paramount to configure your Kubernetes infrastructure properly for optimal system security.

‍

Without further ado, let's dive right into it.

Impact of misconfigurations on Kubernetes

Misconfigurations can result in several noteworthy concerns, including the following:

• Misconfigurations generally augment the attack surface, thereby increasing the system's vulnerability. Frequently, individuals utilize default configurations, leading to security threats, as cyber attackers can gain access to the entire host through a single object or resource as a gateway.
• Network policy-related misconfigurations can culminate in inadequate traffic management, as they don't restrict access to endpoints and ports, which malicious users can exploit as entry points.
• Resources that lack limitation rules can be "hijacked" by malicious actors for purposes such as crypto-mining or as a backdoor to execute malware.
• If Kubernetes configurations aren't established based on security recommendations, users can access sensitive information, which they can then modify or employ to seize control of the entire system.

Common types of Kubernetes misconfigurations

Here are some of the most common Kubernetes misconfiguration:

• Privileged containers present a significant risk to the host's security. If a container is allotted CAP_SYS_ADMIN permissions, the value of allowPrivilegeEscalation is true. Consequently, if any user gains access to the container, they can penetrate the entire host, seizing complete control.
• Execution programs like cmd.exe or bash must be eliminated from the container. If left ignored, these can grant users the liberty to execute a shell script within the container, which presents an unauthorized access gateway that potentially serves as a backdoor for running malware.
• It's relatively common for users to be granted a cluster-admin role, which, although an easy solution to operational problems, poses a significant threat due to the extensive permissions it grants users. This instance is more dangerous than appropriately applying role-binding to a user, as it authorizes the user to execute any command on any resource, thus creating a significant system vulnerability.
• DevOps engineers often overlook blocking network access points via ingress and egress filters. Similar to earlier misconfigurations, this too creates a security loophole because it doesn't regulate the traffic that can access specific ports or endpoints.
• Setting up immutable container file systems in Kubernetes can help alleviate the damage if a cyber attacker infiltrates the system. That said, it's still paramount to enforce other security measures like network segmentation, access controls, and monitoring to protect the container.Frequently, container images are used without reviewing or altering default configurations, which can pose a grave issue since these configurations are often too permissive and don't adhere to the principles of zero trust and least privilege.
• Often, the importance of limiting unnecessary traffic is overlooked, which can have severe repercussions on Kubernetes security. Proactive efforts like setting network policies restrict unnecessary communications between objects and can prevent potential malicious attacks.
• By default, Kubernetes secrets are encrypted as base64-encoded strings in etcd, a distributed key-value store used by Kubernetes for configuration data storage. Anyone can access etcd by decoding the Secret and modifying it, making it vital to encrypt Kubernetes Secrets using tools like OpenSSL, Vault, SOPS, or
• KMS.Linux environments are frequently unhardened, thereby leaving the cluster susceptible to security breaches. It's essential to harden the environment via security services like SELinux, AppArmor, and seccomp. Though SELinux is enabled by default starting with Kubernetes v1.22, it's crucial to verify this setting.
• Often, engineers mistakenly leave the control plane exposed to an untrusted network. Preventing such errors is as simple as establishing SSH tunneling between the API server and Kubelet or verifying the Kubelet serving certificate.

How ARMO Platform solves Kubernetes misconfigurations

Outlined below are the methods by which misconfigurations can be detected and resolved utilizing the ARMO Platform:

Automated vulnerability and configuration scanning

Automated configuration scanning offers the ability to continuously detect system loopholes and promptly notify engineers who can resolve them. Following preliminary cluster deployment, the vulnerability scanner inspects container images and identifies potential security threats.

The same process occurs when new container images are incorporated into the system. This systematic approach enables the timely rectification of security issues and other errors resulting from misconfigurations. Subsequent scans can be manually initiated, event-triggered, or scheduled periodically, thereby increasing the likelihood of early detection and rectification of misconfigurations.

Suggested remediation for risks and vulnerabilities

Depending on the vulnerabilities and misconfigurations identified by the scanner, the ARMO Platform recommends potential remedies for misconfigurations and fixes for vulnerabilities. These suggestions can be seamlessly filtered and prioritized via a visual dashboard, where the platform guides users toward implementing the necessary fixes.

RBAC visualizer

Role Based Access Control (RBAC) plays a crucial role in Kubernetes configurations. It empowers organizations to determine who has access to certain system privileges. The ARMO Platform provides an RBAC visualizer, a tool that showcases all users along with their respective privileges. This visualizer makes it easy to access and query such critical information.

Best practices for Kubernetes configurations

Kubernetes configuration files must be stored in a Version Control System (VCS). Approvals should be managed so that, when one person makes changes, their peers can review these amendments before they are committed to the main branch. Besides, maintaining configuration files in the VCS contributes to the audit trail of changes and strengthens the cluster's security.

‍

Utilizing YAML for crafting configuration files is more advantageous than using JSON, mainly because the former is easier for humans to read. As such, it becomes simpler for team members to comprehend the configuration and rectify it if needed.All associated objects should be consolidated into a single file because managing, troubleshooting, and operating on one file is more straightforward than handling multiple files.

‍

Refrain from using default values, as misconfigurations can inevitably lead to vulnerabilities in the Kubernetes infrastructure. Network policies play an essential role in determining which objects can interact and what incoming traffic can access these objects. Even though, by default, all objects can communicate with each other, these settings must be modified to establish specific rules of access. By doing so, if a malicious attack occurs, the attacker will be hindered from moving across multiple objects due to the restricted attack surface.

‍

To limit internal traffic, firewall implementation is necessary. This ensures that only IPs from an approved list can send requests to the API, thereby preventing unauthorized access to the cluster.

Conclusion

In conclusion, one of the most frequent causes behind security breaches in Kubernetes clusters is misconfiguration. While there are many potential misconfigurations, the utilization of solutions like the ARMO Platform and Kubescape, coupled with adherence to the best practices outlined above, can significantly reduce the likelihood of such errors. Consequently, this results in a fortified Kubernetes cluster characterized by a minimized attack surface.