MFA, cross account roles and command line

One primary #AWS account #security tool is #IAM roles. My practice is that user without MFA can't do anything. I force the user to assume the role before she can do anything. This can be real pain if you have to manage multiple accounts. Also Terraform has some “issues” with MFA so assuming the role and setting up the credentials to the environment variables is the simplest solution.

The best tool to manage this chaos is awsume. Before using it you have to setup your credentials properly to the shared credentials.

To ~/.aws/credentials I set up the "main account".

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[mainaccount] aws_access_key_id = <accesskey> aws_secret_access_key = <secret key>

The IAM policy does not require MFA for this yet. It doesn’t allow many actions either. Actually if the MFA is not used, then this account is only allowed to set the virtual MFA device and change the console password. (But I’ll have another post about that later…)

At ~/.aws/config I have:

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[profile dev-website-admin] role_arn = arn:aws:iam::1234566543321:role/Admin source_profile = otherprofile mfa_serial = arn:aws:iam::1234566543324:mfa/myaccountt

Now the credentials are properly set. To assume the role with awsume you only need:
awsume dev-website-admin

It sets the proper temporary credentials and asks the MFA token if that's needed.

AWS Account Alias as part of security

Good AWS practices require that AWS Organizations is used to separate the testing from production. It means that there is multiple AWS accounts to manage. That can be real nightmare where you can accidentally do bad things for the production.

To reduce the risks for accidents I've started to use account aliases to describe which account I'm currently managing. But how to name the accounts? There should be some standard way to name the account. They should clearly tell if the account is dev, testing or production account.

My organization is Bad Boys of Quality. Shortly it's BBoQ. That's good prefix for my accounts. Then dev, test and prod are good labels to describe the state of the environment. The final part should be the descriptive word for the account.

First - and most important account - for organization is master account. It's unique. I've decided that it's production. I've named it to bboq-prod-master. At the shared credentials I've got prod-master-admin profile to administer this account.

At the shared credentials I'm following the same naming convention as account aliases. This way I can easily change my account with awsume.

To set the account alias I would use AWS CLI. I don’t want to mess up the role history of my browser. Before doing anything else I’ve set the role to my shared credentials. I usually use ~/.aws/config for this. So now we are creating alias for bboq-dev-website. First I have to define the shared credential.

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[profile dev-website-admin] role_arn = arn:aws:iam::1234566543321:role/Admin source_profile = otherprofile mfa_serial = arn:aws:iam::1234566543324:mfa/myaccountt

To set the account alias with AWS CLI the line is:
aws iam create-account-alias --account-alias bboq-dev-website --profile dev-website-admin

One cool side is that when you assume the role at AWS web console, you can use the account alias. So instead of cryptic Admin @ 123456654321 you are Admin @ bboq-dev-website. This reduces the amount on confusions. It again underlines what kind of account is I'm managing. Destruction at dev account shouldn't be bad, but destruction at production is.

So why the account alias is part of security and safety? The more clearly you see things, more easily you notice if something is wrong, and less mistakes you make. I can tell you that before I started to use account alises at naming, I got almost totally lost what I was doing. Juggling with account ids is nearly impossible when you have than 2 accounts. And we have… almost 10 already and part of the teams doesn’t have them yet.

So there is six accounts: development, test and production website and three support accounts. Accounts are named bboq-dev-website, bboq-test-website and bboq-prod-website. Then there’s several support accounts like bboq-prod-accounts (all IAM users are here), bboq-prod-master, bboq-prod-compliance (all logs are going to this one).

Next post will present some ideas how to enhance readability and safety with Terraform and account aliases.