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AWS credentials, MFA, and role profiles

When onboarded, you will be provided with an AWS user. You can use it to access the AWS console at: https://teaching-vacancies.signin.aws.amazon.com/console.

  • Log in to the console, go to IAM and find your user: IAM users.
  • Choose Assign MFA device and set up an authenticator app as a Virtual MFA device. Note: You may need to name the MFA device the same as your username.
  • If using an Authenticator App, scan the QR code, and when prompted to enter codes, enter the first code, wait 30 seconds until a new code has been generated on your authenticator app, and enter the new code in the second box.
  • Log out, and back in. You should be prompted for an MFA code.
  • Go to IAM and find your user again: IAM users
  • Choose Create access key. Note the credentials securely, as you will need these to configure the AWS CLI.

Assuming a role in the console

  • When you log in to AWS you will have permissions to
    • Change your password
    • Set up an MFA device
    • Generate Access Keys To carry out more privileged operations, you will need to switch to a role
  • Choose your user name on the navigation bar in the upper right. It typically looks like this: @teaching-vacancies.
  • Choose Switch Roles.
  • For Account, enter 530003481352
  • For Role, enter ReadOnly
  • For Display Name, this will be greyed out as ReadOnly @ 530003481352
  • Pick a colour for the role display and click Switch Role
  • Choose Switch Roles again
  • For Account, enter 530003481352
  • For Role, enter SecretEditor
  • For Display Name, this will be greyed out as SecretEditor @ 530003481352
  • These two roles should now be listed in your Role History

Roles

  • Administrator can:
    • administer the AWS account, and all resources, including user and group management
  • BillingManager can:
    • access invoices and other billing information
    • read all resources
  • Deployments can:
    • deploy apps and resources
  • ReadOnly can:
    • read all resources
  • SecretEditor can:
    • read and update existing secrets within Parameter Store

Tool installation

Install:

macOS

brew install awscli
brew install --cask aws-vault

Ubuntu WSL2

The setup on Ubuntu is more involved, as we use GPG and pass for a secure vault backend

Install AWS CLI v2

curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip"
unzip -q awscliv2.zip -d /tmp
sudo /tmp/aws/install

Install AWS Vault

wget https://github.com/99designs/aws-vault/releases/download/v6.2.0/aws-vault-linux-amd64
sudo mv ./aws-vault-linux-amd64 /usr/local/bin/aws-vault
sudo chmod +x /usr/local/bin/aws-vault

Install GPG and Pass

sudo apt-get install -y gnupg pass

There's an excellent guide to managing password with GPG, the command line and Pass but the essentials are:

Generate GPG Key

gpg --full-generate-key

Answer the interactive questions. I chose

Please select what kind of key you want:
   (1) RSA and RSA (default)
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (3072)
    3072
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0)
    2y

You are then prompted for some personal details

GnuPG needs to construct a user ID to identify your key.

Real name: <YOUR-NAME>
Email address: <YOUR-NAME>@digital.education.gov.uk
Comment: Work
You selected this USER-ID:
    "<YOUR-NAME> (Work) <<YOUR-NAME>@digital.education.gov.uk>"

You are then prompted for a passphrase to protect the GPG key. I used my Windows password manager to generate and store the passphrase

After moving the mouse to generate random bytes for prime generation, we see:

gpg: key 8C6B1A2FA5910DE0 marked as ultimately trusted
gpg: revocation certificate stored as '/home/nrubuntu/.gnupg/openpgp-revocs.d/A5896473017A0DD9B983A03D8C6B1A2FA5910DE0.rev'
public and secret key created and signed.

pub   rsa3072 2021-02-11 [SC] [expires: 2023-02-11]
      A5896473017A0DD9B983A03D8C6B1A2FA5910DE0
uid                      <YOUR-NAME> (Work) <<YOUR-NAME>@digital.education.gov.uk>
sub   rsa3072 2021-02-11 [E] [expires: 2023-02-11]

Typing gpg --list-keys will repeat the output of pub, uid, and sub

Secure password-store with GPG key

pass init <GPG-PUB-ID from step above>

Append to ~/.bashrc or ~/.zshrc

export AWS_VAULT_PASS_PREFIX=aws-vault
export AWS_VAULT_BACKEND=pass

Configure AWS CLI with AWS Vault profiles

Edit or create the ~/.aws/config file, and paste this in, replacing <YOUR-AWS-USERNAME> in the three places it appears:

[profile teaching-vacancies]
mfa_serial=arn:aws:iam::530003481352:mfa/<YOUR-AWS-USERNAME>
region=eu-west-2

[profile ReadOnly]
mfa_serial=arn:aws:iam::530003481352:mfa/<YOUR-AWS-USERNAME>
region=eu-west-2
role_arn=arn:aws:iam::530003481352:role/ReadOnly
source_profile=teaching-vacancies

[profile SecretEditor]
mfa_serial=arn:aws:iam::530003481352:mfa/<YOUR-AWS-USERNAME>
region=eu-west-2
role_arn=arn:aws:iam::530003481352:role/SecretEditor
source_profile=teaching-vacancies

If needed, two other profiles can also be included for the Deployments and Administrator roles.

[profile Deployments]
mfa_serial=arn:aws:iam::530003481352:mfa/<YOUR-AWS-USERNAME>
region=eu-west-2
role_arn=arn:aws:iam::530003481352:role/Deployments
source_profile=teaching-vacancies

[profile Administrator]
mfa_serial=arn:aws:iam::530003481352:mfa/<YOUR-AWS-USERNAME>
region=eu-west-2
role_arn=arn:aws:iam::530003481352:role/Administrator
source_profile=teaching-vacancies

Then use AWS Vault to set the credentials:

aws-vault add teaching-vacancies

You'll be prompted to enter ID of an Access Key you created here, and the key itself, which you saw when you created it:

Enter Access Key ID:
Enter Secret Access Key:

Then you will see:

Added credentials to profile "teaching-vacancies" in vault

Log in to the AWS Console with AWS Vault

Log in and switch to the ReadOnly role:

aws-vault login ReadOnly

You should be prompted for an MFA code:

Enter token for arn:aws:iam::530003481352:mfa/<YOUR-AWS-USERNAME>:

You should see a link with a very long SigninToken

https://signin.aws.amazon.com/federation?Action=login&Issuer=aws-vault&Destination=https%3A%2F%2Fconsole.aws.amazon.com%2F&SigninToken=CfTUyKvXf1Xq3qjTRUNCATED

Work with the AWS CLI on the command line

Refresh the .env file

aws-vault exec ReadOnly -- make -s local print-env > .env

List the S3 buckets

aws-vault exec ReadOnly -- aws s3 ls

Rotate AWS credentials for AWS Vault

Rotate your AWS access keys at least every 90 days with this command:

aws-vault rotate teaching-vacancies

Use the AWS CLI without AWS Vault

In this example you will use your personal Access Key and Secret key in the [teaching-vacancies] profile

If for any reason you had issues with the AWS Vault tool, you could use the AWS CLI directly by:

aws configure --profile teaching-vacancies

You'll be prompted:

AWS Access Key ID [None]: AKIA
AWS Secret Access Key [None]: GXdB
Default region name [eu-west-2]:
Default output format [None]:

And then running e.g.

aws s3 ls --profile ReadOnly

Assuming an AWS role without AWS Vault

In this example you will use your personal Access Key and Secret key in the [default] profile, and are able to use third-party tools which do not understand the AWS --profile option, such as Terraform.

aws configure

You'll be prompted:

AWS Access Key ID [None]: AKIA
AWS Secret Access Key [None]: GXdB
Default region name [eu-west-2]:
Default output format [None]:

There is a useful Gruntwork blog

Generate an MFA token in your Authenticator App, then use it in this command

aws sts get-session-token --serial-number arn:aws:iam::530003481352:mfa/<YOUR-AWS-USERNAME> --token-code <MFA-token>
aws sts assume-role \
  --role-arn arn:aws:iam::530003481352:role/ReadOnly \
  --role-session-name <YOUR-AWS-USERNAME> \
  --serial-number arn:aws:iam::530003481352:mfa/<YOUR-AWS-USERNAME> \
  --token-code <MFA-token>

You will see temporary session credentials, which have a duration of one hour

{
    "Credentials": {
        "AccessKeyId": "AKIAIOSFODNN7EXAMPLE",
        "SecretAccessKey": "wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY",
        "SessionToken": "AQoEXAMPLEH4aoAH0gNCAPyJxz4BlCFFxWNE1OPTgk5TthT+FvwqnKwRcOIfrRh3c/LTo6UDdyJwOOvEVPvLXCrrrUtdnniCEXAMPLE/IvU1dYUg2RVAJBanLiHb4IgRmpRV3zrkuWJOgQs8IZZaIv2BXIa2R4OlgkBN9bkUDNCJiBeb/AXlzBBko7b15fjrBs2+cTQtpZ3CYWFXG8C5zqx37wnOE49mRl/+OtkIKGO7fAE",
        "Expiration": "2021-03-16T19:23:20+00:00"
    },
    "AssumedRoleUser": {
        "AssumedRoleId": "AROAXWZVLKMEK2POASFO6:<YOUR-AWS-USERNAME>",
        "Arn": "arn:aws:sts::530003481352:assumed-role/ReadOnly/<YOUR-AWS-USERNAME>"
    }
}

Using the examples above, set these as environment variables:

export AWS_ACCESS_KEY_ID=AKIAIOSFODNN7EXAMPLE
export AWS_SECRET_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY
export AWS_SESSION_TOKEN=AQoEXAMPLEH4aoAH0gNCAPyJxz4BlCFFxWNE1OPTgk5TthT+FvwqnKwRcOIfrRh3c/LTo6UDdyJwOOvEVPvLXCrrrUtdnniCEXAMPLE/IvU1dYUg2RVAJBanLiHb4IgRmpRV3zrkuWJOgQs8IZZaIv2BXIa2R4OlgkBN9bkUDNCJiBeb/AXlzBBko7b15fjrBs2+cTQtpZ3CYWFXG8C5zqx37wnOE49mRl/+OtkIKGO7fAE

It may be easier to copy and paste without the examples, like so:

export AWS_ACCESS_KEY_ID=
export AWS_SECRET_ACCESS_KEY=
export AWS_SESSION_TOKEN=

If you need to renew your session, you'll need to first unset the environment variables (starting a new terminal will usually have the same effect)

If generating these sessions is a regular activity, then you may find this snippet helpful. It uses jq to extract the three values, before setting them as environment variables:

sessionInfo="$(aws sts assume-role --role-arn arn:aws:iam::530003481352:role/ReadOnly --role-session-name <YOUR-AWS-USERNAME> --serial-number arn:aws:iam::530003481352:mfa/<YOUR-AWS-USERNAME> --token-code 123456)"
export AWS_ACCESS_KEY_ID="$(echo $sessionInfo | jq '.Credentials.AccessKeyId' | tr -d '"')"
export AWS_SECRET_ACCESS_KEY="$(echo $sessionInfo | jq '.Credentials.SecretAccessKey' | tr -d '"')"
export AWS_SESSION_TOKEN="$(echo $sessionInfo | jq '.Credentials.SessionToken' | tr -d '"')"

Rotating deploy user access key

The deploy user is an AWS account and it is used to run the CI/CD. Both its access key and access_key_id are stored on Github Secrets (AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY). For security reasons, the access key needs to be rotated occasionally e.g. every 3 months

The deploy user and its access key ( aws_iam_access_key ) are deployed via the common terraform module. Please note, these resources are not deployed via the CI\CD pipeline.

To rotate the key, please do the following:-

  • [] From the root of the project, change directory - cd terraform/common/
  • [] aws-vault exec Administrator -- terraform apply -replace aws_iam_access_key.deploy
  • [] aws-vault exec Administrator -- terraform output -json - note the newly generated ACCESS_KEY_ID and ACCESS_KEY.
  • [] Copy the newly generated ACCESS_KEY_ID and ACCESS_KEY to Github secrets - AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY.
  • [] Test by running/triggering a deploy workflow or run a workflow_dispatch action