this post was submitted on 18 Aug 2023
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Almost every program that we run has access to the environment, so nothing stops them from curling our credentials to some nefarious server.

Why don't we put credentials in files and then pass them to the programs that need them? Maybe coupled with some mechanism that prevents executables from reading any random file except those approved.

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[–] [email protected] 33 points 1 year ago (2 children)

I have a rule that credentials in environment variables are to only ever be loaded as needed via some sort of secrets manager, optionally adding a wrapper script to do so transparently.

The whole point of passing secrets as environment variables is to avoid having things in files in plain and in known locations easy to scrape up by any malware.

Now we have people going full circle and slapping those into a .env file.

[–] [email protected] 3 points 1 year ago (2 children)

But how do you authenticate to your secret manager? How do you prevent evil scripts from also doing this?

[–] [email protected] 2 points 1 year ago

I type my password, or on the work MacBook, TouchID. I'd imagine yubikeys would do too.

[–] [email protected] 1 points 1 year ago

You could decrypt a GPG key-based file to do that.

[–] [email protected] 2 points 1 year ago (1 children)

I'd be very thankful for an example of your setup. I'm using Bitwardern for browser-related password management, but for convenience scripts I load the credentials as env vars at login through .bash_profile 😅

[–] [email protected] 4 points 1 year ago (1 children)

Basically just have each sets of credentials in a script, and whenever you need to use something that needs a key, you source the script you need first.

Then each of those scripts are something like

export MY_API_KEY="$(bw get password whatever)"
[–] [email protected] 1 points 1 year ago
[–] [email protected] 26 points 1 year ago (1 children)

No no see the credentials have been towed outside the environment.

[–] [email protected] 12 points 1 year ago

The frontend fell off!

[–] [email protected] 22 points 1 year ago

The classic Unix user and permission system provides a solution for this.

Create a user for the app you are worried about. Make the environment variables available to that user only.

Other apps can’t read the secrets, and if the app itself gets exploited, it has access to the secrets in any case.

[–] [email protected] 11 points 1 year ago

I suppose in a well configured Docker or Kubernetes environment this doesn't matter that much. Also, in Kubernetes, "secrets" can be passed as read-only files.

[–] [email protected] 10 points 1 year ago

If you run a binary written with bad intentions, you're doomed anyway.

This is the security model we have currently.

[–] [email protected] 7 points 1 year ago* (last edited 1 year ago)

CRED=$(fancy-get-cred) do-stuff

do-stuff has ${CRED} but nothing else does. wrap in a shell script.

[–] [email protected] 5 points 1 year ago

Global credentials are yuck

[–] [email protected] 5 points 1 year ago (1 children)

CyberArk is a commercial product that attacks this problem space. It puts an agent process on the host next to your app. Only processes whose fingerprint matches those authorized to access a credential are allowed to fetch it. That fingerprint can be based on the host (known list of production hosts), the os user ID that owns the pid, the path to the executable for the pid, and probably a few more items.

Under that model your app just needs to know the environment that it wants (inject however you want) and the userid it wants to use. At runtime it reaches out to the local cyberark agent to obtain the password secret.

[–] [email protected] 6 points 1 year ago (1 children)

Under this model, a proprietary, closed source process can access all your secrets.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

great point...is there an open source equivalent?

[–] [email protected] 1 points 1 year ago (1 children)

no, because there are superior approaches already, some of them you can find in this post

[–] [email protected] 1 points 1 year ago (1 children)
[–] [email protected] 2 points 1 year ago

eh... good luck

[–] [email protected] 5 points 1 year ago

What's the goal?

There are extra steps you can take to try to improve the security against malware, but using environment variables instead of hard coding isn't really intended for that, I don't think.

It's just to stop accidental leaks with stuff like git and other code sharing.