We're attempting to build a generic microservice for secrets into our HashiCorp Vault. We'd like it to be generic enough that other teams within the company can use it as well as our own team. We will REQUIRE AppRole security and policies on each and every secret store and will also be building our own trusted orchestrator for the AppRole Tokens.
How would we need to setup the URL's for it to be generic enough to allow everyone to be able to access only their own secrets? I was thinking something like this:
machinename.servicename.local/roleId/secretId/nameSpace/secretsPath
Obviously it would be a POST vs. a GET because it would be machine to machine with no human interaction at all.
Related
Many of my (confidential) apps are talking to each other via the client credential flow.
They request a token from the Azure Identity platform and use this token to authenticate against another app.
A while ago I used client secrets to do so, but later I read that this is not recommended for production environments.
For this reason I changed to self-signed certificates that are valid a longer time.
Those certificates are generated by myself with Azure Keyvault.
However, also this is not recommended.
Microsoft states that that in production environments you should use certificates that are signed by an official CA.
If I now use Lets encrypt, this will expire all three months what is also not such a nice solution.
My questions:
Why is the client secret not recommended in production environments?
Why is the self-signed certificate a problem? I do understand this in matters of HTTPS, but where is the security breach if its used for client credential flow? In my case I am the owner of the app and the app registration.
Do I need to buy a certificate that is one-year valid to do it "the right way"?
Do you have any source of best practices here?
• Client secrets include application credentials, SSH keys, API keys, database passwords, encryption keys, connection strings and so on to connect various resources and access the data or functionality for achieving the designated purpose of that application. Thus, if these are breached, they can put your application at great risk of compromise. Also, the client secret generated in Azure AD and used in APIs for connecting to Azure AD for authentication and authorization purpose is listed and mentioned in unencrypted form in the API code itself. Though, we have an option to store that secret in a key vault and refer to that secret through either managed identity or RBAC assignments, but their credentials too can fall in wrong hands and let the application be vulnerable if the managed identity is a user assigned or even if then access scope of the secret is not well defined according to the required specific need. Thus, client secret is not recommended to be used in a production API.
• In client credentials flow, applications are directly granted permissions by an administrator to perform a certain action regarding the API to be called through it via certificate or federated credentials. Thus, when using a self-signed certificate in client credentials grant scenario, the administrator has granted the daemon app requesting access to other API all the required privileges regarding accessibility of code, API, permissions, data, etc. which can result in poor validation and misuse as the it is very easy to generate a certificate’s key pair without reasonable entropy. Also, protecting the private key of the key pair appropriately to its use and strong validation of the same is not promised in a self-signed certificate due to which it is not recommended in client credentials flow.
• For best practices regarding web app service deployment, please refer to the documentation link below: -
https://learn.microsoft.com/en-us/azure/app-service/security-recommendations#general
It explains the best security recommendations for deploying a web app service.
We have a bunch of Windows server applications that currently handle secrets as follows; our apps are in C#.
We store them in settings files in code
We store them encrypted, using a certificate
The servers have this certificate with the private key, so they can decrypt the secret
We're looking at implementing Hashicorp Vault. It seems easy enough to simply replace the encrypt-store-decrypt with storing the secret in Vault in the KV engine, and just grabbing it in our apps - that takes that certificate out of the picture entirely. Since we're on-prem, I'll need to figure out our auth method.
We have different apps running on different machines, and it's somewhat dynamic (not as much as an autoscaling scenario, but not permanent - so we can't just assign servers to roles one time and depend on Kerberos auth).
I'm unsure how to make AppRole work in our scenario. We don't have one of the example "trusted platforms" or "trusted entities", there's no Nomad, Chef, Terraform, etc. We have Windows machines, in a domain, and we have a homegrown orchestrator that could be queried to say "This machine name runs these apps", so maybe there's something that can be done there?
Am I in "write your own auth plugin" territory, to speak to our homegrown orchestrator?
Edit - someone on Reddit suggested that this is a simple solution if our apps are all 1-to-1 with the Windows domain account they run under, because then we can just use kerb authentication. That's not currently the way we're architected, but we've got to solve this somehow, and that might do it nicely.
2nd edit - replaced "services" with "apps", since most of our services aren't actually running as Windows services, just processes. The launcher is a Windows service but the individual processes it launches are not.
How about Group Managed Service Accounts?
https://learn.microsoft.com/en-us/windows-server/security/group-managed-service-accounts/group-managed-service-accounts-overview
Essentially you created one "trusted platform" (to your key vault service).
Your service can still has its own identity but delegation to the gMSA when you want to retrieve the secrets.
For future visibility, here's what we landed on:
TLS certificate authentication. Using Vault, we issue a handful of certs, each will correspond to a security policy/profile, so that any machine that holds that certificate will be able to authenticate and retrieve the secrets they should have access to.
Kerberos ended up being a dead-end for two reasons. The vault.exe agent (which is part of this use case) can't use the native Windows Kerberos SSPI, so we'd have to manage and distribute keytab files. Also, if we used machine authentication, it would blow up our client count (we're using the cloud-hosted HCP Vault, where pricing is partially based on client count).
Custom plugins can't be loaded into the HCP, of course
Azure won't work, it requires Managed Identities which you can't assign to on-prem machines. Otherwise this might have been a great fit
We have installed and configured Hashicorp Vault AppRole authentication for one server, by storing the role_id and secret_id in a local file on the server, and we're able to have code on the server read the values from file, authenticate to Vault, receive a token and then read the secrets it needs from Vault. So far so good. However, the secret_id expires after 31 days, and so the process fails.
I've read up on the concepts of using AppRoles, and they seem like the perfect fit for our use case, but for this expiration. We don't want to have to re-generate the secret_id every month.
From what I've read, if you create the role without setting secret_id_ttl it should be non-expiring, but that isn't the case. This may be due to how the AppRole auth method is configured, but I haven't seen anything solid on this.
So I found an article on the Hashicorp website where AppRoles are discussed in detail. The article gives good arguments for expiring secret_id's in a CI/CD environment, even illustrating how this works in 8 simple steps. I understand how this works, but the article fails to mention how the CI/CD and Orchestrator systems themselves are authenticated to Vault? Or am I missing something?
In the end, I want to have the secret_id not expire. Ever.
Without additional support from your environment you will have to write some logic in your installer, and have a service manager of some sort to start your services. In many cloud environments, you may already have the equivalent entities (Terraform, Cloud Formation, etc.) and you should leverage their secrets management capabilities where needed.
For custom installations, here is a workflow that I have used.
Have an installation manager process that can be invoked to perform installation / upgrade. Make sure installation / upgrade of services is always through this process.
Have a service manager process that is responsible for starting individual services and monitoring them / restarting them. Make sure service start-ups are always via this service manager.
During installation, generate self-signed certificates for Vault, installation manager and service manager. Vault certificates should trust the certs for the installation manager and the service manager. Store these with limited permission (600) in directories owned by the installation user or the service manager user as the case may be. Set up certificate-based authentication in Vault using these certs.
These credentials should have limited capabilities associated with them. The installation manager should only be able to create new roles and not delete anything. The service manager should only be able to create secrets for the named roles created by the installation manager, and delete nothing.
During installation / upgrade, the installation manager should connect to Vault and create all necessary service-specific roles. It should also be able to set role ids for individual services in per-service config files that the services may read on start-up.
During each service's start-up, the service manager should connect to Vault and create secret ids corresponding to each service's role. It should set the secret id in an environment variable and start the service. The secret id should have time-bound validity (by setting TTLs) so that they cannot be used for much beyond the creation of the auth token (see #7).
Each service should read the role id from the config file, and the secret id from the environment variable. It should then generate the auth token using these two, and use the token to authenticate itself with vault for its lifetime.
It is possible to create a Vault AppRole with a secret_id that essentially never expires. However, this should be limited to use on a Vault development server -- one that does not contain any production credentials -- and for use in a development environment.
That being said, here's the procedure I used based on several articles in the Vault documentation, but primarily AppRole Pull Authentication.
This assumes that the Vault approle authentication method is already installed at approle/ and that you are logged in to Vault, have root or admin privileges on the Vault server and have a valid, non-expired token.
Note: For the values supplied for the fields below, the maximum value that vault seems to accept is 999,999,999. For the TTL fields, that is the number of seconds which comes out to more than 31 years. That's not forever, but it is long enough that renewing the secret_id will probably be somebody else's problem (SEP).
# Vault server address to be used by the Vault CLI.
export VAULT_ADDR="https://vault-dev.example.com:8200/"
# Vault namespace to be used by the CLI.
# Required for Cloud and Enterprise editions
# Not applicable for Open Source edition
export VAULT_NAMESPACE="admin"
# The name of the Vault AppRole
export VAULT_ROLE=my-approle
# Override defaults on the approle authentication method
# NOTE: In this command, the field names, default-lease-ttl
# and max-lease-ttl contain dashes ('-'), NOT
# underscores ('_'), and are preceded by a single
# dash ('-').
vault auth tune \
-default-lease-ttl=999999999 \
-max-lease-ttl=999999999 approle/
# Override defaults on the approle
# NOTE: In this command, the field names, secret_id_ttl and
# secret_id_num contain underscores ('_'), NOT
# dashes ('-'), and are NOT preceded by a single
# dash ('-').
vault write auth/approle/role/my-approle \
secret_id_ttl=999999999 \
secret_id_num_uses=999999999
# Create a new secret_id for the approle which uses the new defaults
vault write -f auth/approle/role/my-approle/secret-id
Update the server config file to use the new secret_id and you are ready to go.
As the OP has noted, the Hashicorp Vault documentation assumes that the application is able to authenticate, somehow, to the vault and then retrieve the secret ID (possibly wrapped) from the vault and then, use that to authenticate and fetch a token used to actually work with secrets. The answers here are posing alternative approaches to retrieving that initial token.
Alan Thatcher wrote a blog article, Vault AppRole Authentication, that provides another well thought out approach:
Create a policy that allows the user to retrieve the secret-id and role-id, but nothing else.
Create a long lived, periodic/renewable token based on that policy.
Store the long lived token securely, e.g. as a Kubernetes secret
At runtime, use the long-lived token to:
acquire the secret-id and role-id,
authenticate to vault using these and acquire short-lived token
use current short-lived token to work with secrets
For Java applications, the Spring Vault project supports this approach if you configure the long-lived token as the "initial token" and the approle authencation name, e.g. chef-ro in the blog case.
My personal feeling is that this approach is about as secure but a bit simpler than the mutual TLS approach. I agree that using an infinite TTL for the secret-id is a less secure practice for Production environments.
Thanks to Mr. Thatcher for thinking this one through.
This is probably not the canonnical answer, but I found it empty so decided to add some pointers.
As per Hashicorp Vault AppRole: role-id and secret-id:
Additional brownie information: Ideally, it's best practice to keep
the TTL low, 30 minutes max - if your application is stateful, or
maybe even less if it's a stateless application. The secret key of
Vault approle should also be rotated every 90 days. Please note by
default, Vault approle backend has 31 days of TTL, so if you want to
set it to 90 days, you need to increase TTL of the approle backend as
well.
However (in the same question):
You can generate secret-id with indefinite validity. But doing so will
be as good as keeping your secrets in the configuration file.
For ephemeral instances you can use configuration management to pass in secrets via a third (broker) role. With regard to a server that exists indefinitely, i'm still working that out...
Ideas:
TLS certificates might work well on Windows, don't know about Linux.
GitHub Personal Access Tokens, but this is not org. friendly.
Review the other auth methods available to see if there's one that fits your requirements (e.g. AWS).
Is it possible to use AWS KMS and a tool like credstash without the use of EC2 or equivalent or does it rely solely on IAM roles?
I've got a server elsewhere where I am testing some things out and ultimately I will be looking at migrating an app to EC2 etc. to make use of scaling. But for now whilst I'm setting up my deployment pipeline etc. I wondered if it was still possible to make use of KMS on my non-aws provisioned server?
The only possible way I can think of is by installing the AWS CLI tools on the server in question. Does this sounds like the right approach?
What #Viccari said is correct (in the comments). In terms of what you want to do (store passwords), the AWS Parameter Store would be a good fit for you. See https://docs.aws.amazon.com/systems-manager/latest/userguide/systems-manager-paramstore.html for more information. The guide explicitly calls out your use-case:
Parameter Store offers the following benefits and features.
Use a secure, scalable, hosted secrets management service (No servers to manage).
In the end, if you end up using Parameter Store or KMS, you will need some sort of credentials stored somewhere to grab an AWS STS token to use to call the underlying AWS services. If working outside of AWS EC2, you will need the AWS Access Key and AWS Secret Key from an IAM user. If you are in EC2, the IAM instance role will magically provide you the credentials and use that role to call those AWS services. The AWS SDK does this for you behind the scenes.
But, as you state, you don't want to run this in EC2 (to save money, or other reasons). The quickest way to store these credentials is to have them in a un-tracked file (added to your .gitignore) you can source from as environment variables, which your program will then read. This allows you to do local testing, and easily run it in EC2
with zero code changes. See https://docs.aws.amazon.com/cli/latest/userguide/cli-environment.html for what variables to set. Note that this doc talks about the CLI; the SDK's follow the same behavior.
I'm looking into vault for securing DB credentials used by various web applications. I've looked over a few Youtube videos, slide shares and even downloaded Vault to experiment with. I can't quite wrap my head around it.How does Vault protect credentials for something like a web application which uses a token to authenticate to Vault with? I'm assuming the Apache process would have to own the vault token (user token, not root token) so it can access secrets for the applications it's running. This would, it seems, expose any secrets the Apache process would have access to in the event of an application compromise. I don't see a big win here so I must be missing a lot.
In a nutshell, Vault supports authentication backends which then allow you to generate tokens. Tokens should be seen as temporary access and are not the same as a key.
In particular, Vault supports authentication with many different systems to generate dynamic secrets and credentials as needed. This is well documented here
In terms of security, the idea is to have a authentication backend as the primary, and the token being generated as a consequence. You are correct in saying hard coding tokens is a security risk. Once generated on the fly, they should have strict permissions and short TTLs. Vault makes this easy as you can define the scope of the token with an ACL.