vArmor : Enhancing Container Security In Cloud-Native Environments

vArmor is a cloud-native container sandbox system. It leverages Linux’s AppArmor LSM, BPF LSM and Seccomp technologies to implement enforcers.

It can be used to strengthen container isolation, reduce the kernel attack surface, and increase the difficulty and cost of container escape or lateral movement attacks.

You can leverage vArmor in the following scenarios to provide sandbox protection for containers within a Kubernetes cluster.

• In multi-tenant environments, hardware-virtualized container solutions cannot be employed due to factors such as cost and technical conditions.
• When there is a need to enhance the security of critical business containers, making it more difficult for attackers to escalate privileges, escape, or laterally move.
• When high-risk vulnerabilities are present, but immediate remediation is not possible due to the difficulty or lengthy process of patching. vArmor can be used to mitigate the risks (depending on the vulnerability type or exploitation vector) to block or increase the difficulty of exploitation.

vArmor Features:

• Cloud-native. vArmor follows the Kubernetes Operator design pattern, allowing users to harden specific workloads by manipulating the CRD API.
  • This approach enables sandboxing of containerized microservices from a perspective closely aligned with business needs.
• Supports the use of AppArmor, BPF, Seccomp enforcer individually or in combination, enforcing mandatory access control on container file access, process execution, network outbound, syscall, and more.
• Supports the Allow by Default security model, in which only behaviors explicitly declared will be blocked, thus minimize performance impact and enhancing usability.
• Supports behavior modeling, and provides protection based on behavior models, meaning only behaviors explicitly declared are permitted.
• Ready to use out of the box. vArmor includes multiple built-in rules for direct use.

vArmor was created by the Elkeid Team of the endpoint security department at ByteDance. And the project is still in active development.

Note: To meet stringent isolation requirements, it is advisable to give priority to utilizing hardware-virtualized containers (e.g., Kata Containers) for compute isolation, in conjunction with network isolation provided by CNI’s NetworkPolicy.

Prerequisites

You can specify the enforcer through the spec.policy.enforcer field of policy objects (VarmorPolicy/VarmorClusterPolicy). In addition, you can also use different enforcers individually or in combination, such as: AppArmorBPF, AppArmorSeccomp, AppArmorBPFSeccomp etc.

The prerequisites required by different enforcers are as shown in the following table.

Enforcer	Requirements	Recommendations
AppArmor	1. Linux Kernel 4.15 and above 2. The AppArmor LSM is enabled	GKE with Container-Optimized OS AKS with Ubuntu 22.04 LTS VKE with veLinux 1.0 Debian 10 and above Ubuntu 18.04.0 LTS and above veLinux 1.0 etc.
BPF	1. Linux Kernel 5.10 and above (x86_64) 2. containerd v1.6.0 and above 3. The BPF LSM is enabled	EKS with Amazon Linux 2 GKE with Container-Optimized OS VKE with veLinux 1.0 (with 5.10 kernel) AKS with Ubuntu 22.04 LTS * ACK with Alibaba Cloud Linux 3 * OpenSUSE 15.4 * Debian 11 * Fedora 37 veLinux 1.0 with 5.10 kernel etc. * Manual enabling of BPF LSM is required
Seccomp	1. Kubernetes v1.19 and above	All Linux distributions

The Policy Modes And Built-In Rules

The vArmor policy can operate in five modes: AlwaysAllow, RuntimeDefault, EnhanceProtect, BehaviorModeling and DefenseInDepth.

When the policy is running in EnhanceProtect mode, built-in rules and custom interfaces can be used to harden the container.

For more information, please refer to Policy Modes and Built-in Rules.

For more information click here.