It's 2018. Are My Containers Secure Yet!?
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The document discusses the state of container security. It notes that while container security has improved significantly from early Docker implementations, there are still challenges. Container isolation features have known vulnerabilities and lightweight virtualization is gaining popularity for added security. The document outlines security considerations for container hosts, images, runtimes and usability, and discusses emerging projects aimed at further enhancing security such as Project Grafeas, libentitlements, and LinuxKit. It concludes that open source projects now provide tools to securely isolate containers with defense-in-depth, and vendors offer solutions to guide users in configuring container platform security.
It's 2018. Are My Containers Secure Yet!?
- 1. @estesp IT’S 2018. ARE MY CONTAINERS SECURE YET?! DevOps Pro Vilnius
- 2. @estesp HELLO! 2 Phil Estes > Office of the CTO, IBM Cloud > Docker Captain > Docker engine contributor > Containerd and Moby Project maintainer
- 3. @estesp 1. A BRIEF OVERVIEW Easing into containers: the what and why of security 3
- 4. @estesp CONTAINERS AREN’T REAL (@jessfraz) ◈ Containers on Linux are an assembly of Linux kernel isolation features ◈ These features have been developed independently ◈ Significant use and testing has improved these areas over the past several years, but... 4 CGROUPS + NAMESPACES + SECURITY FEATURES Memory, CPU, Disk Mount, User, Network, UTS, IPC, Cgroup.. AppArmor, SELinux, Seccomp, Caps
- 5. @estesp CONTAINERS AREN’T PERFECT ◈ Kernel isolation features continue to have CVEs ◈ Hedging on lightweight virtualization has gained popularity (e.g. Hyper.sh, Intel Clear Containers) ◈ Docker and Kubernetes have added other elements to “containers” that require security awareness: ◆ Container Images (mini OS images!) ◆ Container Networking ◆ Storage/Volumes/Secrets ◆ Orchestration/Distributed Systems security 5
- 6. @estesp WHAT DO WE WANT FROM CONTAINERS? > Isolation from host > Security from other tenants > Resource limits > Secure SW supply chain > Immutability > Repeatability/reproducability 6
- 7. @estesp SECURITY HAS IMPROVED SIGNIFICANTLY ◈ Docker focused on security in 2016-2017 ◆ Application secrets, better “sane by default” policies (AppArmor, Seccomp), User namespaces, Swarm mode node security, image signing, secure image format/protocol ◈ Security vendor offerings around containers has exploded in the past 24 months ◈ Project Grafaes, Entitlements, Kubernetes security improvements are all recent advancements ◈ Defense-in-depth model is a valuable approach 7
- 8. @estesp 2. HOST SECURITY Container runtimes run on a Linux (or Windows) server 8
- 9. @estesp HOST OS SECURITY ◈ Containers use a shared kernel ◆ Escapes through kernel would affect all containers ◆ --privileged should be used very sparingly ◈ Root on container runtime most likely means root on system ◈ Tenancy: single tenancy per node? Multi-tenancy with VMs? 9 BARE METAL {or} VM HOST OS/KERNEL CONTAINER RUNTIME { orchestrator } CTR CTR CTR Image Registry
- 10. @estesp 3. CONTENT SECURITY Containers images are an important part of a security posture 10
- 11. @estesp CONTAINER IMAGE/CONTENT SECURITY ◈ (Base) Images updated regularly ◆ Use image scanning tools ◆ Don’t treat containers like VMs! ◈ Least privilege mentality: ◆ No root user ◆ Minimal, read-only if possible ◆ Drop privileges ◈ Image signing & provenance (Docker Content Trust/Notary) 11 BARE METAL {or} VM HOST OS/KERNEL CONTAINER RUNTIME { orchestrator } CTR CTR CTR Image Registry
- 12. @estesp 4. RUNTIME SECURITY What security capabilities exist for container runtimes? 12
- 13. @estesp CONTAINER RUNTIME/ORCHESTRATOR SECURITY ◈ Understand deployment choices ◆ RBAC? Who has access to API? ◆ Storage, Network, Volume plugins ◆ Feature switches (e.g. require image signing) ◈ Will you use lightweight virtualization to improve container isolation? ◈ Secrets implementation 13 BARE METAL {or} VM HOST OS/KERNEL CONTAINER RUNTIME { orchestrator } CTR CTR CTR Image Registry
- 14. @estesp 5. USABLE SECURITY If security isn’t usable, then it probably won’t be used 14
- 15. @estesp SECURITY WITHOUT USABILITY = NO SECURITY > Developers will disable security features if they get in the way of progress and/or successful software deployment. > Developers won’t learn how to enable security features. They are too busy. Features must be enabled with sane defaults. 15
- 16. @estesp THE SECURITY CONUNDRUM ◈ Who will decide what is “secure” for your business? ◆ Myriad of choices require expertise to make decisions ◈ Developers will turn off intrusive security ◈ DevOps implications ◆ CI/CD impact (source/upstream hygiene, image scanning, provenance/signing, promotion policies) ◆ Security vendors offering UX to bring “manageability” to help with choices, configuration, auditing 16
- 17. @estesp STEPS ON THE RIGHT PATH ◈ Container runtimes ◆ Out of the box “sane defaults” ◆ Docker (AppArmor, Seccomp profiles built-in) ◆ Kubelet choices: “secure” or “untrusted” container models ◈ An Example: Docker Swarm Mode ◆ Built-in certificate authority deployment, full TLS intranode encryption, certificate rotation, node secure ID ◆ Kubernetes working on similar improvements, but componentized model of K8s makes it more challenging 17
- 18. @estesp 6. SECURITY FUTURES What’s coming next? What improvements will enable better security for the future? 18
- 19. @estesp NEW PROJECTS AND NEW IDEAS ◈ Project Grafaes (potentially Kritis) ◈ libentitlement (Moby project) ◈ LinuxKit: using image labels (for defining capabilities/etc.) ◈ Kubernetes runtimes: using annotations to select trust level of runtimes 19
- 20. @estesp PROJECT GRAFEAS > Open, common metadata server API for representing vulnerability/incident data for container images > Cross-vendor commitment to publish in Grafeas format (Google, IBM, Twistlock, Aqua, Redhat, etc.) 20 https://github.com/grafeas/grafeas
- 21. @estesp MOBY PROJECT: LIBENTITLEMENTS > Uses concept of Android permission model > Developers need to understand broad container permission requirements > Library will translate that to low-level isolation constructs 21 https://github.com/moby/libentitlement Android App Permissions: ACCESS_WIFI_STATE BLUETOOTH BLUETOOTH_ADMIN BROADCAST_STICKY CHANGE_NETWORK_STATE CHANGE_WIFI_MULTICAST_STAT E CHANGE_WIFI_STATE DISABLE_KEYGUARD EXPAND_STATUS_BAR GET_PACKAGE_SIZE INSTALL_SHORTCUT INTERNET KILL_BACKGROUND_PROCESSES MODIFY_AUDIO_SETTINGS
- 22. @estesp ANNOTATIONS: HINTS FOR CONTAINER RUNTIMES > A Kubernetes CRI implemention can support multiple underlying container runtimes and use annotations to decide which one (more secure, less secure) to use > In this case, cri-o can use lightweight virtualization (Intel Clear Containers) for better isolation of untrusted code 22 io.kubernetes.cri-o.TrustedSandbox: “false”Example:
- 23. @estesp LINUXKIT: COMBINING SECURITY CONCEPTS > Uses image label to specify runtime config (e.g. security settings for image) > Image signing and trust required (on by default) > Minimal host OS (tiny userspace, runs containers for services) 23 https://github.com/linuxkit/linuxkit https://github.com/linuxkit/kubernetes
- 24. @estesp 7. SUMMARY Conclusions on the state of container security 24
- 25. @estesp THE STATE OF CONTAINER SECURITY ◈ Vastly improved from early days of Docker engine ◈ Open source projects have all the right knobs for securing and isolating containers ◈ Vendors providing turnkey solutions for those who want a guided UX to security ◈ Work continues to make security more usable, with sane defaults for your platform 25
- 26. @estesp WHAT CAN YOU DO? ◈ Implement “defense in depth” ◆ If one layer of your protection fails, another one may either limit blast radius or also defend against the attack ◈ Understand building blocks of container security ◆ Host ◆ Runtime ◆ Image ◆ Platform-provided (Kubernetes, networking, etc.) 26
- 28. @estesp CREDITS Special thanks to all the people who made and released these awesome resources for free: ◈ Presentation template by SlidesCarnival 28