http://AssimilationSystems.com/ 1/14 Distributing Secrets Securely to Distributing Secrets Securely to Containers Containers Alan Robertson Charter Communications AlanR@unix.sh @OSSAlanR Founder: Linux-HA project Assimilation Project

http://AssimilationSystems.com/ 2/14 Agenda Agenda ● What’s a secret? ● What does it mean to protect a secret? ● So what’s the problem? ● Two solutions: – Custodia – Custom Code

http://AssimilationSystems.com/ 3/14 What’s a Secret? What’s a Secret? ● These kinds of things are often secrets: – Passwords, Application Tokens, Secret keys, AWS keys, etc. ● You’re storing them so machines (and humans) have access to them ● It might be something small and internal ● It might be something a bit more important ● It might be the “Keys To The Kingdom”

http://AssimilationSystems.com/ 4/14 What does protecting a secret What does protecting a secret mean? mean? ● Don’t store them in plain text on disk ● Don’t pass them as command line parameters, or environment variables ● Don’t store them in GitHub... ● This is harder than it sounds...

http://AssimilationSystems.com/ 5/14 So what’s the problem? So what’s the problem? ● If you cannot protect your Vault key, then your secrets are at risk ● If an attacker compromises your application, they probably have access to your vault key... ● If you could protect your Vault key, you could probably protect your secrets ● Vault software helps but is not enough ● We need to be able to protect our keys!

http://AssimilationSystems.com/ 6/14 What to do? What to do? ● Don’t store vault keys in your containers ● Identify and validate your application without using keys they need to protect ● How to do this?

http://AssimilationSystems.com/ 7/14 UNIX sockets to the rescue! UNIX sockets to the rescue! ● UNIX domain sockets allow authentication of the application that’s connecting – User ID – Group ID – Process ID – Security Context (SE Linux)

http://AssimilationSystems.com/ 8/14 This helps you get even more This helps you get even more information from information from ● /proc ● Docker inspect This gives you analogous to the DNA of the caller – the cyber analog of biometrics Authenticate your caller with just this information

http://AssimilationSystems.com/ 9/14 /proc interesting things /proc interesting things ● /proc//cmdline - client command line ● /proc//cgroup – identifies the container ● /proc//exe - full pathname client binary ● /proc//uid_map (and gid_map) ● /proc//status – uid/gid info, ppid

http://AssimilationSystems.com/ 10/14 Docker inspect interesting things Docker inspect interesting things ● Name - the name of the image ● Path - full pathname of the container's "init" process ● Args - the arguments given to the init process in the container ● State.Pid - the process id of the container's "init" process ● Config.Hostname - hostname of this container ● Config.Image - the image name that client is running in ● Image - the SHA256 sum of "Config.Image"

http://AssimilationSystems.com/ 11/14 Red Hat’s Custodia Red Hat’s Custodia

http://AssimilationSystems.com/ 12/14 Could it be simpler? Could it be simpler? ● Custodia: – Proxies the entire secret management infrastructure – Duplicate configuration with Vault – Larger attack surface (even though it’s good code) ● What if you just provided vault keys? – Each client just gets a vault key when authenticated – Clients use key to connect directly to vault

http://AssimilationSystems.com/ 13/14 An alternative approach An alternative approach

http://AssimilationSystems.com/ 14/14 References References ● Custodia article: – peerlyst.com/posts/sharing-secrets-with- containers-using-custodia-alan-robertson ● Authproxy article: – peerlyst.com/posts/the-authproxy-method-of- sharing-secrets-safely-with-containers-alan- robertson