Storing sensitive values in state files

[seanherron]

#309 was the first change in Terraform that I could find that moved to store sensitive values in state files, in this case the password value for Amazon RDS. This was a bit of a surprise for me, as previously I've been sharing our state files publicly. I can't do that now, and feel pretty nervous about the idea of storing state files in version control at all (and definitely can't put them on github or anything).

If Terraform is going to store secrets, then some sort of field-level encryption should be built in as well. In the meantime, I'm going to change things around to use https://github.com/AGWA/git-crypt on sensitive files in my repos.

[bitglue]

See #874. I changed the RDS provider to store an SHA1 hash of the password.

That said, I'm not sure I'd agree that it's Terraform's responsibility to protect data in the state file. Things other than passwords can be sensitive: for example if I had a security group restricting SSH access to a particular set of hosts, I wouldn't want the world to know which IP they need to spoof to gain access. The state file can be protected orthogonally: you can not put it on github, you can put it in a private repo, you can use git-crypt, etc.

[kubek2k]

related #689

[dentarg]

Just want to give my opinion on this topic.

I do think Terraform should address this issue. I think it will increase the usefulness and ease of use of Terraform.

Some examples from other projects: Ansible has vaults, and on Travis CI you can encrypt informaton in the .travis.yml file.

[ketzacoatl]

Ansible vaults is a feature I often want in other devops tools. Protecting these details is not as easy as protecting the state file.. what about using consul or Atlas as a remote/backend store?

+1 on this

[dayer4b]

I just want to point out that, according to official documentation, storing the state file in version control is a best practice:

https://www.terraform.io/intro/getting-started/build.html

Terraform also put some state into the terraform.tfstate file by default. This state file is extremely important; it maps various resource metadata to actual resource IDs so that Terraform knows what it is managing. This file must be saved and distributed to anyone who might run Terraform. We recommend simply putting it into version control, since it generally isn't too large.

(emphasis added)

Which means we really shouldn't have to worry about secrets popping up in there...

[hobbeswalsh]

:+1: on this idea -- it would be enough for our case to allow configuration of server-side encryption for S3 buckets. Any thoughts on implementing that?

[apparentlymart]

At the risk of adding scope to this discussion, I think another way to think of this is that Terraform's current architecture is based on a faulty assumption: Terraform assumes that all provider configuration is sensitive and that all resource configuration isn't sensitive. That is wrong in both directions:

• Several resources now take passwords as inputs or produce secret values as outputs. In this issue we see the RDS password as one example. The potential Vault provider discussed in #2221 is another example.
• Several provider arguments are explicitly not sensitive, such as the AWS region name, and excluding them from the Terraform state results in Terraform having an incomplete picture of the world: it can see that there is an EC2 instance with the id i-12345 but it can't see what region that instance is in without help of the configuration. Changing the region on the AWS provider causes Terraform to lose track of all of the existing resources, because as far as the AWS provider is concerned they've all been apparently deleted.

So all of this is to say that I think overloading the provider/resource separation as a secret/non-secret separation is not the best design. Instead, it'd be nice to have a mechanism on both sides to distinguish between things that should live in the state and things that should not, so that e.g. generated secrets can be passed into provisioners but not retained in the state, and that the state can encode that a particular instance belongs to a particular AWS region and respond in a better way when the region changes.

There are of course a number of tricky cases in making this situation, which I'd love to explore some more. Here are some to start:

• If you don't retain something in the state then it's not safe to interpolate it anywhere because future runs will assume they can interpolate attributes from existing resources in the state.
• Some provider config changes effectively switch all resources to an entirely new "namespace", and thus effectively force every attached resource to be destroyed and recreated in the new region. The AWS region is one example, since AWS resources are region-specific. But that's not so simple for other arguments: the AWS access_key might change what Terraform has permission to interact with, but it doesn't change the id namespace that resources live within.

[little-arhat]

Hi, any progress on that? Terraform 0.6.3 still stores raw passwords in the state file. Also, as a related issue, if you do not want to keep passwords in configuration, you can create variable without default value. But, this will force you to pass this variable every time you run plan/apply, even if you're not going to change resource that has this password.

I think, it would be nice to separate sensitive stuff from other attributes, so it will:

• be stored as sha1 or smth in state file
• not require value if it already has one.

So, for configuration like:

variable db {
    password {}
}

resource ... {
    password = "${var.db.password}"
}

terraform will require variable for the first run, when it doesn't have anything, but will not require on subsequent runs.

To change such value one need to provide different value for password.

[EvanKrall]

Maybe there's a simple solution: store the state in Vault?

[mwarkentin]

A good solution for this would be useful for us as well - we're manually configuring certain things to keep them out of the tfstate file in the meantime.

[ascendantlogic]

So as I slowly cobble together another clean-sheet infra with Terraform I see this problem still exists, and this issue is almost exactly 1 year old. What is the thinking in regards to solving this? the ability to mark specific attributes within a resource as sensitive and storing SHA1 or SHA2 hashes of their values in the state for comparison? I see this comment on a related ticket, does that mean that using Vault will be the prescribed way? I get that it promotes product synergy but I'd really like a quick-n-dirty hashing solution as a fallback option if I'm honest.

[ketzacoatl]

Moving secrets to vault, and using consul-template or integration with other custom solutions you have for CM certainly helps for a lot of cases, but completely avoiding secrets in TF or ending up in TF state is not always reasonable.

[ascendantlogic]

Sure, in this particular case I don't want to manually manage RDS but I don't want the PW in the state in cleartext, regardless of where I keep it. I'm sure this is a somewhat common issue. Maybe an overarching ability to mark arbitrary attributes as sensitive is shooting for the moon but a good start would be anything that is obviously sensitive, such as passwords.

[jfuechsl]

Would it be feasible to open up state handling to plugins? The standard could be to store it in files, like it is currently done. Other options could be Vault, S3, Atlas, etc.

That way this issue can be dealt with appropriately based on the use-case.

[brikis98]

I just got tripped up by this as well, as the docs explicitly tell you to store .tfstate files in version control, which is problematic if passwords and other secrets end up in the .tfstate files. At the bare minimum, the docs should be updated with a massive warning about this. Beyond that, there seem to be a few options:

1. Offer some way to mark variables as secret and either ensure they never get stored in .tfstate files or store them in a hashed form.
2. Encrypt the entire .tfstate file.
3. Remove the recommendation to store .tfstate files in version control and only recommend them to be stored in secure, preferably encrypted storage.

[ejoubaud]

One thing to consider around this is output. When you create a resource with secrets (key pair, access keys, db password, etc.), you likely want to show the secret in question at least once (possibly in the stdout of the first run, as output do)

Currently output are also stored in plain text in the .tfstate, and can be retrieved later with terraform output.

One possible solution would be a mechanism to only show the secrets once, then not store them at all and not show them again (like AWS does), possibly using only-once output as I suggested in #4437

[revett]

+1

[sstarcher]

+1

[ascendantlogic]

To get around this for now in my production RDS I just created the instance with a password of changeme1234 and then went to the console and manually changed the PW.

[gtmtech]

+1

I notice also that Redshift is imminently going to be supported on terraform, and the same mistakes are being made all over again:

master_password - (Required) Password for the master DB user. Note that this may show up in logs, and it will be stored in the state file

"Applications should not transmit or store passwords in unencrypted form"

Page 77 - ISO27001 :

https://books.google.co.uk/books?id=Ur1lviHCd-4C&pg=PA77&dq=no+password+unencrypted+disk+iso27001&hl=en&sa=X&ved=0ahUKEwibuMrywb3KAhUCVxQKHR7yCNwQ6AEIPTAB#v=onepage&q=no%20password%20unencrypted%20disk%20iso27001&f=false

Can this please not be done - it instantly means for lots of us (for compliance reasons) we cant use it - the whole "no password should be written down on any disk unencrypted" thing is a killer.

This has been in progress for over a year - is there any attempt to solve this? I would have thought the simplest approach would be to hash the password, store the hash.

[johnrengelman]

@gtmtech a hash isn't cryptographically safe either because it can be reversed. The right solution here is something that can store the value securely, doing anything else IMO would be a waste of energy.

[ketzacoatl]

@gtmtech, if this is a blocker, can you put in a goof password on first run, and then manually update it, as @ascendantlogic notes above? While not "clean", and while it "gives you something to do", that seems like a reasonable middle ground, no?

[ascendantlogic]

@johnrengelman forgive me if I am misunderstanding, but I thought hashes were, by definition, one way. Or at least any reasonable use of one to add some level of protection to secrets necessitates the use of a one-way?

[gtmtech]

So problems with the comments above are:

• A goof password will mean every time we terraform plan it will advise us it wants to rewire the password - not a great experience when we're always after clean terraform states, but you're right its probably the only workaround we have right now so thanks for the suggestion...
• A hash is one-way, and yes if you use SHA1, or even SHA256 you deserve everything you get, but there are other hash functions that are pretty secure - they are one way, and in ANY case, it would fulfil compliance and allow people to use the resource.

Maybe there's a way of not storing the password at all, and not caring about it? When I worked on configuration management tools before, I did this approach sometimes - it was never stored in state, and the value was always set to be ignored, so the diff algorithm just completely ignored it, but it was used on first create only. This isnt ideal either as you cant manage passwords with TF, but its better than unencrypted, readable master database passwords everywhere.

Its a real shame to not be able to use terraform for something as dumb as plaintext readable master passwords, its such a great tool otherwise!

[johnrengelman]

@ascendantlogic ah yeah, sorry, don't know where my brain was this morning. I'm blaming that fact that I hadn't had coffee yet.

[gtmtech]

I would recommend bcrypt or even scrypt for the password hashing.

In the meantime, a goof password with ignore_changes=["master_password"] will suffice so long as I can get terraform to NOT store it in the state file.

A meta_parameter to accomplish not storing a particular atribute would be an alternative to having to do the hashing work - either one could accomplish the end goal

[sstarcher]

@gtmtech A goof password should not cause terraform states to complain every time. As long as the password in the tf files and the password in the state file are the same terraform should be happy.

I created a RDS database using a password in the TF files and after creation went into the TF file and changed it to XXXXX. I also went into the state file and change it to XXXXX. terraform plan and terraform apply are happy.

[gtmtech]

@sstarcher interesting, what happens when you terraform refresh, does it not override your XXXXXing out of the password?

[sstarcher]

@gtmtech nothing happens it continues to work happily. The state file still contains XXXXX as terraform has no way of knowing what the actual database password is.

I just tested to confirm the following results in no change and my password in the tf state is still XXXXX which is not my actual password

• terraform refresh
• terraform plan

[ascendantlogic]

@gtmtech that is not what happens. I modified the password after the fact in the console and TF is perfectly happy. I think it only wants to change the PW on the RDS resource if the value in the tf file doesn't match the tfstate file, the AWS API does not return the RDS password for TF to compare against the tfstate, that would be madness.