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A Better Way to Manage the Rails Secret Token

daniel.fone.net.nz

41–50 of 60 posts

Re: A Better Way to Manage the Rails Secret Token

#41

We've had discussions about this several times, and haven't come up with something that's satisfactory as a generic replacement, other than "configuration could probably be improved." For one example, see this from a year ago: https://github.com/rails/rails/pull/3777#issuecomment-289375... > If we ignore them, this means a recently created, pushed and then cloned project is not going to work at all. Some people repla…

[deleted]

Re: A Better Way to Manage the Rails Secret Token

#42

Earlier quoted context omitted.

That's a bit surprising. I'd be interested to read the reasoning behind this design decision as most frameworks I have used store session data in a database rather than directly in the cookie. Well I guess there is a pretty damn good reason given Rails' reputation.

Rails' default session is cookie store, highly recommended is DB. It's a config issue that depends on your app's particular DB setup, so default isn't DB. But in session_store.rb you'll see this comment recommending against the default: # Use the database for sessions instead of the cookie-based default, # which shouldn't be used to store highly confidential information # (create the session table with "rails generat…

also, in config/initializers/secret_token.rb:

   # Your secret key for verifying the integrity of signed cookies.
Does this mean that if you use redis/db-backed sessions you can safely ignore this secret_token parameter completely or even delete this initializer?

UPDATE: I just tried to remove it from our environment, and everything seems fine. Unless I'm missing something out, I'd say that's a far better and easier solution overall. It gives you much better control over you session + you don't have to worry about this configuration variable.

Re: A Better Way to Manage the Rails Secret Token

#43
post #35
post #32

Your environment is not secure. The solution for this type of problem (keeping secrets out of source control) is to create a deployment-specific configuration file that is not kept in source control. It can be created out of a generic version that is kept in source control. Then, OS-level permissions are applied so the file is only readable by the processes that need access.

How is the environment any less secure than memory? If someone can read or mutate your environment, you should assume your app is already compromised and OS-level permissions aren't going to do anything.

Most people probably set the environment for all processes not just on a need to know basis perhaps.

Re: A Better Way to Manage the Rails Secret Token

#44
post #18

For Python website projects, I enforce the creation of a _secrets.py file in the config folder that is ignored by git and contains all sensitive constants like database information and tokens. Then, in the _base.py settings file (what all other settings files inherit from), I make sure to `from _secrets import *`. I'm not a fan of setting tokens by environment because it gets a little too unwieldy to make sure bash/z…

For me the main reason is consistency. I can write apps in Python, Ruby, node, etc. and configure them all the same way.

The envdir program (from daemontools) is useful for setting environment variables in a shell-agnostic way, e.g., run your app with:

  envdir ./env python app.py
See also

http://12factor.net/config

Re: A Better Way to Manage the Rails Secret Token

#45
post #34

I don't understand why a secret token is even necessary. This seems like bad design. As a matter of principle, the server should never trust the client. If authentication is necessary, it should be done on every request. If that is the case, what purpose does the token serve? The entire principle behind HTTP - what enabled it to conquer and dominate the internet, is its statelessness. Storing and trusting things in c…

I'm not sure you understand what's going on, which is probably why you've been downvoted. The secret token ensures that the server does not need to trust the client--that's what signing or encrypting session cookies does.

Authentication on every request requires you to store the user's authentication details on the client, which is considerably worse for security purposes than a signed or encrypted session cookie.

Re: A Better Way to Manage the Rails Secret Token

#46
post #45
post #34

I don't understand why a secret token is even necessary. This seems like bad design. As a matter of principle, the server should never trust the client. If authentication is necessary, it should be done on every request. If that is the case, what purpose does the token serve? The entire principle behind HTTP - what enabled it to conquer and dominate the internet, is its statelessness. Storing and trusting things in c…

I'm not sure you understand what's going on, which is probably why you've been downvoted. The secret token ensures that the server does not need to trust the client--that's what signing or encrypting session cookies does. Authentication on every request requires you to store the user's authentication details on the client, which is considerably worse for security purposes than a signed or encrypted session cookie.

I wrote this comment with the assumption that we all understand the security implications of what's going on, which is why I probably did a poor job of making my point.

However, I think that relying on a single easy-to-compromise security token as a single point of failure for your app's security is terrible practice.

A secure user authentication system is usually built by having a users database that contains [user_id, nonce, password_key = pbkdf2(password, nonce)]. When logging the user in, you should store this information in a cookie: [user_id, login_timestamp, authentication_token = hmac-sha256(nonce, login_timestamp, password_key)]. Then, on every subsequent request, you would verify that the authentication_token matches what you'd expect based on the login_timestamp and user_id that the client has provided. (Substitute this for any equivalent-security scheme and crypto primitives.)

Now, if you have such a scheme in place, a secret token would provide no additional security. You really shouldn't be storing session information in cookies, but if you must, you can use a key derived from the nonce to sign the cookie, removing the need for an app-global secret. But really, don't do that, you should use a server side datastore for session information (like shopping carts, etc.).

If you do not have such a scheme in place, you app is much more vulnerable to attack. Something based on one global secret token (which by default is checked in to your source code) opens up many more attack vectors that might compromise the security of your app.

Re: A Better Way to Manage the Rails Secret Token

#47

Earlier quoted context omitted.

> Session data is marshal-ed Ruby data, deserializing it has the same risks as YAML.load. http://daniel.fone.net.nz/blog/2013/05/20/a-better-way-to-ma...

That's a bit surprising. I'd be interested to read the reasoning behind this design decision as most frameworks I have used store session data in a database rather than directly in the cookie. Well I guess there is a pretty damn good reason given Rails' reputation.

It is often useful to not have to store anything server-side and just round-trip signed data in the cookie. Of course, using a format that can execute code on deserialisation is still a bad idea: a successful attack on the signature should at most let someone impersonate a user, not do anything to an app.

Re: A Better Way to Manage the Rails Secret Token

#48
post #35
post #32

Your environment is not secure. The solution for this type of problem (keeping secrets out of source control) is to create a deployment-specific configuration file that is not kept in source control. It can be created out of a generic version that is kept in source control. Then, OS-level permissions are applied so the file is only readable by the processes that need access.

How is the environment any less secure than memory? If someone can read or mutate your environment, you should assume your app is already compromised and OS-level permissions aren't going to do anything.

Certain weird-shit UNIX operating systems do not provide privacy for a process's environment. (eg. another user on the same box can see them with 'ps e'). More relevantly, POSIX does not require it. The same is not true of process memory.

Re: A Better Way to Manage the Rails Secret Token

#49
post #32

Your environment is not secure. The solution for this type of problem (keeping secrets out of source control) is to create a deployment-specific configuration file that is not kept in source control. It can be created out of a generic version that is kept in source control. Then, OS-level permissions are applied so the file is only readable by the processes that need access.

It's worth noting that with 'dotenv' the configuration is stored in a file on the production server before it's loaded into the environment. The security of the method is not based on storing the token in the environment.

The primary advantage I intended was that the secret is confined to one part of the infrastructure (e.g. production server) instead of many (e.g. developer workstations, github, etc).

Re: A Better Way to Manage the Rails Secret Token

#50

We've had discussions about this several times, and haven't come up with something that's satisfactory as a generic replacement, other than "configuration could probably be improved." For one example, see this from a year ago: https://github.com/rails/rails/pull/3777#issuecomment-289375... > If we ignore them, this means a recently created, pushed and then cloned project is not going to work at all. Some people repla…

Have you considered generating a key at first startup and storing it in a database? Or would that introduce too much unnecessary overhead while introducing an attack vector through the database?

The extra overhead could be kept pretty small. After being retrieved once, it can be cached in the memory of a server process. So, there's one short SQL query at process startup (or perhaps first request, depending on how you do it), and negligible overhead after that.
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