Container Security

10 Apr 2024

Abusing search permissions on Docker directories for privilege escalation

A privilege escalation vulnerability was discovered in Docker environments where the /var/lib/docker directory has search permissions for other users. Low-privileged attackers can access container filesystems by exploiting these permissions. By modifying container startup scripts and leveraging host reboot capabilities, attackers can potentially gain root access on the host system.

2 Feb 2024

runc working directory breakout (CVE-2024-21626)

A critical vulnerability in runc (CVE-2024-21626) allows attackers to break out of container filesystems by exploiting a file descriptor leak. The flaw enables setting a container's working directory to the host filesystem, potentially granting unauthorized access to host systems in Kubernetes and containerized environments. Attackers can leverage this vulnerability to access host filesystems, execute malicious code, and potentially compromise multi-tenant Kubernetes clusters.

Golan Myers
12 Jun 2023

Executing Arbitrary Code & Executables in Read-Only FileSystems

This article explores methods of executing arbitrary code in read-only Kubernetes pod file systems. Three techniques are demonstrated for bypassing read-only filesystem restrictions, including using in-memory execution, exploiting /dev/shm, and leveraging dynamic program loaders. The research highlights the complexity of container security and the need for multi-layered defense strategies.

3 Jul 2020

Helping root out of the container

A container breakout technique exploits AF_LOCAL sockets to smuggle file descriptors into a container. By passing a file descriptor for the root directory, a root user within the container can modify files outside its mount namespace. This attack demonstrates how root access in a container can compromise intended security isolation boundaries.

11 Jun 2020

Abusing access to mount namespaces through /proc/pid/root

Linux namespaces can be abused for privilege escalation in containerized environments. Two key attack vectors are demonstrated: creating block devices in Docker containers to bypass access controls and exploiting symlink vulnerabilities through mount and user namespaces. The research highlights potential security risks in container configurations and namespace implementations.

11 Jan 2019

Attacking Kubernetes through Kubelet

A method of attacking Kubernetes clusters by exploiting the default kubelet configuration is detailed in this article. The vulnerability allows anonymous authentication to the kubelet API, enabling attackers to list pods, execute commands in containers, and potentially obtain service account tokens. These tokens can be used to access the kube-apiserver and gain deeper access to the Kubernetes cluster.