Microsecrets, a lightweight secrets manager powered by S3 + KMS

Microsecrets is a secrets distribution tool powered by Amazon S3 and Amazon KMS. It provides a bare-bones approach to passing credentials securely in an Amazon Web Services environment. Credentials are uploaded to S3 and encrypted at rest by KMS. They can then be passed to programs through environment variables.

Installation

$ pip install microsecrets

Usage

Setup

1. Create the S3 bucket you'll use for secrets storage. You may want one bucket per organization, such as example.com-microsecrets.
2. Create one KMS master key for each service that will be using microsecrets. The key should by default be named microsecrets-myservice for a service called myservice. Users uploading the credentials and systems downloading the credentials will need privileges to encrypt/decrypt data using this key. None of the normal users need key administration privileges.

Uploading environment and files

1. Upload environment variable data. Environment variables may be passed as = separated pairs on stdin or in a file. NB: whitespace is stripped and all other characters are treated literally. Or pass them as a JSON dict with the --json flag.

   $ microsecrets-upload -b example-microsecrets -s myservice <<EOM
   DB_URL=db://user:pass@example.com:123
   PASSWORD=hunter2
   EOM

2. Upload a raw file. Usage is the same as uploading environment variables, but you pass a -f LABEL to determine where to upload the file. This example uploads a file from ~/documents/train.txt with label train.txt.

   $ microsecrets-upload -b example-microsecrets -s myservice -f train.txt ~/documents/train.txt

Downloading files to show status

TODO: flesh out this section

1. List latest versions of current files available for download

   $ microsecrets-download -b example-microsecrets -s myservice --list

2. Download the environment

   $ microsecrets-download -b example-microsecrets -s myservice

3. Download files with the environment

   $ microsecrets-download -b example-microsecrets -s myservice -f train.txt:/tmp/train.txt

Running programs under environment with secrets

1. Run a program with the credentials in the environment. To verify the integrity of data in S3, you must specify the checksum of the environment file (output by the upload tool) or whitelist specific environment variables. Or, if integrity is not a concern, whitelist all environment variables. The whitelist is designed to avoid accidentally allowing code execution through LD_PRELOAD or similar, which may or may not be a concern in your system layout.

   $ microsecrets-with-env -b example-microsecrets -s myservice -w 'DB_URL PASSWORD' -- /bin/myserver

See also

There is a variety of other recent work in this space that may be of interest:

• Confidant — https://github.com/lyft/confidant
• Sops — https://github.com/mozilla/sops
• Sneaker — https://github.com/codahale/sneaker
• Credstash — https://github.com/fugue/credstash
• Vault — https://github.com/hashicorp/vault
• Keywhiz — https://github.com/square/keywhiz

License

The project is in the public domain, and all contributions will also be released in the public domain. By submitting a pull request, you are agreeing to waive all rights to your contribution under the terms of the CC0 Public Domain Dedication.

This project constitutes an original work of the United States Government.