If the dev is pushing code to production they should not simultaneously be pushing environment configs, this is doing two logically distinct things at once: Changing application behavior AND reconfiguring the server environment.

If the dev is adding secrets to their local config and they’re pushing that config to insecure places that means their deployment pipeline is broken and it should be fixed. .env is never committed to source for this reason, for example.

It's got a maximum size cap, is trivially introspectable by via any process that can read `/proc`, and sucks at representing hierarchical or structured data beyond k=v.

The proliferation of tools that come up with all sorts of contortions to encode e.g. JSON-ish structures into the environment is evidence that this ain't a great way to go. I hope we're moving towards a container-orchestrator-by-default future; mounting structured data into pseudo-files at runtime is a really nice alternative.

Teach them to use dotenv.

We are moving away from configuration in config files because it is a pain to modify, especially if part of that configuration is secrets. You have to throw everything into your secrets vault of preference, and editing it requires extracting and reuploading the whole thing.

We are currently doing config in env by loading one or multiple secrets per kubernetes pod (mix and match).

What would be your suggestion?

Times have changed since then, and there’s much better tooling available to help with this problem space and surface area these days.

https://dotenvx.com/whitepaper.pdf

This is actually in place in most hosting providers today - don't know if Heroku does it, but many others like Vercel and Fly will also encrypt your secret env vars and decrypt and inject them only at the last minute.

AWS itself has something similar with its secrets manager. Even in the absence of credentials, like using role based IAM when running on EC2, it probably makes sense to note that the code must access credentials by hitting a local-only metadata server - and of course this is available only when running on EC2.

For other secret like payment processor tokens, etc, there's you do need to store secrets somewhere.

Putting secrets in plaintext in the files on the execution platform is of course a problem - but that's not a problem in the 12 Factor idea - it's a security lapse in the design and architecture of the platform that is supposed to be running your 12 Factor app, if that makes sense.

What makes it bad advice?

> this had the second-order effect of leading devs to believe they could put all their local env secrets in ~/.bashrc files

You need some way to pass secrets to the app; doesn't every other way also suffer the same kind of issue?

I was a massive fan of dotenv but sOps is so much cleaner, easy enough to use and works well enough in k8s.

1. Keep secrets in a dedicated secrets store.

2. Read directly from the secrets store in application code. There is no environment, there are no environment variables. Yes, even on local.

Buy-into storing credentials into environment variables.

Then, and this is important - MANAGE YOUR ENVIRONMENTS.

You shouldn't have prod level s3, or aws creds accessible openly in your environment. If someone can steal those values, they can steal the code, and pretty much everything else. This is very bad.

For prod (and possibly staging), use a lib that loads in values securely from an actual secrets service.

For cloud services, it would typically be called a vault. But it could also be a hardware security module (HSM) with bring-your-own-key (BYOK, eg for certificates.)

Ansible also calls it a vault and encrypts it with a password — that file you can check into version control.

The environment is a standard, locate-able, read-only at runtime k/v store in every process. That makes it an incredibly juicy target for exploits. There are tons of remote exploits well short of RCE which can access all or part of a server process's environment. If that environment contains secrets for everything that process might do, that's asking for trouble.

Consider a user-facing webserver with a rarely-used, admin-only route that talks to AWS APIs. Unless it's deployed on AWS and using IMDS, the 12-factor best practices say there should be AWS credentials in its environment.

Consider a service which, at startup, opens a connection to a telemetry/logging system, then drops privileges and handles requests. 12-factor best practices say there should be a secret for that telemetry system in its environment.

Additional examples abound. Most applications (even ones that aren't internet-facing web servers) use configured secrets infrequently--often only once, to open connections to external services--and not during the vast majority of requests they serve, but we put all secrets in the environment anyway.

Vaults don't automatically solve this problem either; many vaults provide secrets to applications by injecting them into process environment at start.

Good secret management at runtime should ideally be:

1. Mutable or at least delete-able. I really wish there were ways to remove environment variables after they're used (so I could say "once you have an authenticated, open socket or a refreshable auth token to $service, remove the initial login secret from memory entirely"), but absent highly complex multi-process/re-exec dances, that doesn't really exist. If, in Python, you 'del os.environ["foo"]', you haven't modified the environment segment of your program's memory.

2. Not in one common/uniform memory area or key-value API. Hell, it's slightly preferable to have secrets be stored piecemeal in regular variables in memory scattered around your code. Those are going to be slightly harder to find for malware that gets a foothold--security by obscurity, true, but the environment memory block/API is such a tempting and easy target that it buys you a bit more than a false sense of security here.

3. Ideally, stored or encrypted in memory (for secrets that have to stay in memory) such that an exploit which can read process memory doesn't get them for free. Some vaults have a host-local sidecar which provides secrets or a decryption key for them; that way, if an attacker gets memory-read without RCE they can't just exfil a memory image and figure out the decryption key later, but you don't have to be reliant on a remote networked service's uptime for all secret accesses. Even if you don't go that far, securing secrets in-memory at least gives you the option of doing zero-trust stuff based on request payloads, or even just making good-hygiene backend APIs that encode "you can only read the value for secret X if the request is for an admin route and authenticated" (which is a good idea for internet-exposed services with seldom-used risky secrets anyway, but doesn't help with parts 1 and 2 if that API is just wrapping env.get() or whatever).

I don't agree, and I think this is personal belief is unfounded. 12 factor apps clearly apply to deployments, not your local dev environment. The whole industry pivoted towards .env files in local dev environments. Local dev tools still store their secrets where they can: local storage.

I would prefer to see secrets from .env not actually splattered in the environment but processed/read on demand, and there are indeed libraries to do that.

The point is that you must keep secrets, and anything environment-specific, out of the code. Follow the spirit of the law, not the letter.

Shoot, I'm sad that Docker didn't become the way to run containers. compose/swarm is still light years easier than Kubernetes

I guess Heroku ran so that Vercel could fly?

The environment was only ever good for things like GOMAXPROCS where you want a single point of truth for all processes on a machine but in a containerized world even that point is moot. Where regular config in the environment just problematic it is outright dangerous for secrets.

I hired about 50 software interns and junior in the past 5 years. None had ever heard of it before I told them.

Both Google and Microsoft call their apps Authenticator, so two identically named apps on my iPhone distinguishable only by logo.

Furthermore, if you login to 20 things a day (which I do), the codes are going to these apps, SMS, and email. Each different.. so if I'm on my Linux box, my Watch doesn't really help. If I leave my phone in the other room, I can't use the apps to get the code without going to the other room. If multi-tasking is expensive for the brain and attention, MFA is the computing surface equivalent.

You may have built a great MFA workflow, but I have to live with 3-10 variations of workflows all day long, including puzzles. And it's more aggravating when I have to MFA to your service to get my information. My machine is in my house and nobody's been in my house but every_single_login requires me to pretend that in every moment of every day someone may have stolen my laptop and my finger.

My work machine will let me auth with my fingerprint, but the typical enterprise integration of all the things means I still have to click through 3-4 screens to get to where the fingerprint is accepted.

Services and APIs don't MFA.. they have keys and other restrictions for seamlessness. Where's the seamlessness solution for humans?

Passkeys are cool, but they're not ubiquitous enough yet, and the interface between desktop and mobile (even using 1Password for universal passkeys) wouldn't qualify as solved in my book.

MFA as whack-a-mole UI sucks.

Passkeys are the right thing but they need more work.