Docker security: Rolling out Trust in your container

Ronak Kogta
Docker Security
Rolling out trust in your container

Buzz is catching on, and so is technology
Neatly packs multiple applications on one
operating system
Gives you way to compose clusters, manage them
and play with them at the scale of 100,000
Docker Docker Docker

 A very secure system which is not user-friendly will not be
secure for long. (because people will find a way to go around it)
 Usable Security is a principle of building security systems
while considering human workflows.
 Speed
 Efficiency
 Learnability
 Memorability
 User Preference
Idea of Usable Security

Its going to be everywhere
 Your Desktop, Workstation & Cloud Infrastructure.
 Your Production, Development & Testing Cycles.
It is going to be used by everyone
 Your team, clients, and partners.
 Independent developers and teams who are using your images.
We should definitely think about #docker-security
Docker Space

 How safe is docker isolation ?
 If some malicious user has docker daemon access, what
to do ?
 Can I use security policies over docker ?
 SELINUX,APPARMOR,GRSEC
 Can I really trust docker image I install ?
 Can i ssh to docker container ?
Lets think..

Every process must be able to access only the information and
resources that are necessary for its legitimate purpose
- Diogo Mónica, Docker
 Linux namespaces (isolated view of system.)
 Cgroups (limit and isolate the resource usage.)
 Linux Security Modules (Apparmor,SELINUX)
 Capabilities
 Per-container ulimit
 User-namespaces: root inside is not root outside
 Seccomp: Individual syscall filtering (like chrome sandbox)
Enter Least Privilege

Cgroups, ulimit & User Namespaces
 Docker root is not real root. (User Namespaces)
 Docker ulimit
 With cgroups, you can control on the resource usage of
container
docker run --lxc-conf=lxc.cgroup.cpuset.cpus = 0,1 ..

 Root has certain capabilities, but we don’t want our
container to have all those capabilities
 Each container can have some of the capabilities of root,
but not all.
 Mounting operations
 Access to raw sockets (prevent opening privileged ports,
spoofing)
 Some file system operations (mkdev, chown, chattrs)
 Loading kernel modules
Capabilites

 man 7 capabilities
 Docker by default drops some capabilities
 sys_admin, sys_time, sys_nice,.....
Capabilites
docker run –cap-drop=CHOWN ...
docker run –cap-add=MKNOD ...

Seccomp & Syscalls
System Calls
OS Utilities
IP Tables
Other User
Programs
Device
Drivers
NetFilter
Other Kernel
Components

Seccomp & Syscalls
 You can block system calls from seccomp. Quite like sandboxing.
 Supports syscall filtering by using BPF
 SIGKILL signal to process, who made blocked syscall
docker run –lxc-conf=common.seccomp ...

More...
 Combine Docker with AppArmor/SELinux/TOMOYO Profiles
 These profiles help you in deciding minimal privilege for each
application.
 Preventing permission escalation and unauthorized information
disclosure (or worse).
 Within the container configuration the related AppArmor profile
can be defined with lxc.aa_profile.
docker run –security-opt label:type:svirt_apche ...

 GRSEC and PaX
 Use a hardened Linux kernel for host, with kernel patches.
 User Mappings
 Map user/group ids
 lxc.id_map = u 0 1000000 65536
 lxc.id_map = g 0 1000000 65536
 Couple it with docker run –lxc-conf=
More...

Can you really trust your images ?
Docker Notary

 Trusted Cross Platform content distribution
 Trusted Client – Server Interaction
 Publisher signed content
 Publisher Key validates integrity of content
 Platform Agnostic to distribute any content
https://github.com/docker/notary
Docker Notary

Docker Content Trust
Publisher Registry
User
User
User

Two keys are generated when publisher first pushes image.
 Tagging Key
 Exists for each new repository that publisher owns
 Can be shared with collaborators easily.
 Offline Key
 Users see this key as official publisher’s key
 Important in establishing trust.
 Only needed when creating new repository or rotating existing
repository
Publisher’s View

 Once Images are signed, TUF maintains ensures
 Integrity
 & Freshness of Content
 Notion of Timestamp Key
 Needed to ensure freshness guarantees
 Generated at remote server.
 Docker maintains it for you
http://theupdateframework.com/
Trust Update Framework

 export DOCKER_CONTENT_TRUST=1
Docker Content Trust

 Security Script that checks for dozens of common best-
practices around deploying Docker containers in produtions.
https://dockerbench.com
DockerBench

Questions ??
IRC: #docker #docker-security
Google Group: Hyderabad Docker Users
Join Docker Movement

Docker security: Rolling out Trust in your container

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