aws-vault

README

AWS Vault

Securely store and access credentials for AWS. AWS Vault stores IAM credentials in your operating systems secure keystore and then generates temporary credentials from those to expose to your shell and applications. It's designed to be complementary to the aws cli tools, and is aware of your profiles and configuration in ~/.aws/config.

Currently the supported backends are:

• macOS Keychain
• KWallet
• freedesktop.org Secret Service
• Encrypted file

Further support for Linux's libsecret and Windows is planned (PRs welcome!).

Installing

Download the latest release.

On macOS, you may instead use homebrew cask to install:

$ brew cask install aws-vault

The macOS release is code-signed, and you can verify this with codesign:

$ codesign -dvv $(which aws-vault) 2>&1 | grep Authority
Authority=Developer ID Application: 99designs Inc (NRM9HVJ62Z)
Authority=Developer ID Certification Authority
Authority=Apple Root CA

Usage

$ aws-vault add home
Enter Access Key Id: ABDCDEFDASDASF
Enter Secret Key: %

$ aws-vault exec default -- aws s3 ls
bucket_1
bucket_2

$ aws-vault add work
Enter Access Key Id: ABDCDEFDASDASF
Enter Secret Key: %

$ aws-vault exec work -- aws s3 ls
another_bucket

Security

Notice in the above how a session token gets written out. This is because aws-vault uses Amazon's STS service to generate temporary credentials them via the GetSessionToken or AssumeRole API calls. These expire in a short period of time, so the risk of leaking credentials is reduced.

The credentials are exposed to the subprocess in one of two ways:

• Environment variables are written to the sub-process.

• Local EC2 Instance Metadata server is started. This approach has the advantage that anything that uses Amazon's SDKs will automatically refresh credentials as needed, so session times can be as short as possible. The downside is that only one can run per host and because it binds to 169.254.169.254:80, your sudo password is required.

The default is to use environment variables, but you can opt-in to the local instance metadata server the --server flag to the exec command.

MFA Tokens

If you have an MFA device attached to your account, the STS service will generate session tokens that are invalid unless you provide an MFA code. To enable MFA for a profile, specify the MFA serial in ~/.aws/config:

[profile default]
mfa_serial=arn:aws:iam::123456789012:mfa/jonsmith

You can retrieve the MFA's serial (ARN) in the web console, or you can usually derive it pretty easily using the format `arn:aws:iam::[account-id]:mfa/[your-iam-username].

Note that if you have an account with an MFA associated, but you don't provide the IAM, you are unable to call IAM services, even if you have the correct permissions to do so.

Assuming Roles

Best-practice is to have a read-only account that you use on a day-to-day basis, and then use IAM roles to assume temporary admin privileges along with an MFA.

First you'll need to setup an MFA token in the AWS Console and create a role with admin access.

Edit your ~/.aws/config to add the role_arn and MFA serial number into a new profile:

[profile read-only]
region=us-east-1

[profile admin]
mfa_serial = arn:aws:iam::123456789012:mfa/jonsmith
source_profile = read-only
role_arn = arn:aws:iam::123456789012:role/admin-access

Then when you use the admin profile, aws-vault will look in the read-only profile's keychain for credentials and then use those credentials to assume the admin role. This assumed role is stored as a short duration session in your keychain so you will only have to enter MFA once per session.

Development

Developed with golang, to install run:

go get github.com/99designs/aws-vault

References and Inspiration

• https://github.com/pda/aws-keychain
• http://docs.aws.amazon.com/IAM/latest/UserGuide/MFAProtectedAPI.html
• http://docs.aws.amazon.com/IAM/latest/UserGuide/IAMBestPractices.html#create-iam-users
• https://github.com/paperg/awsudo
• https://github.com/AdRoll/hologram
• https://github.com/realestate-com-au/credulous
• https://github.com/dump247/aws-mock-metadata
• http://boto.readthedocs.org/en/latest/boto_config_tut.html