AWS Secrets Manager: Store, Distribute, and Rotate Credentials Securely

Today we’re launching AWS Secrets Manager which makes it easy to store and retrieve your secrets via API or the AWS Command Line Interface (AWS CLI) and rotate your credentials with built-in or custom AWS Lambda functions. Managing application secrets like database credentials, passwords, or API Keys is easy when you’re working locally with one machine and one application. As you grow and scale to many distributed microservices, it becomes a daunting task to securely store, distribute, rotate, and consume secrets. Previously, customers needed to provision and maintain additional infrastructure solely for secrets management which could incur costs and introduce unneeded complexity into systems.

AWS Secrets Manager

Imagine that I have an application that takes incoming tweets from Twitter and stores them in an Amazon Aurora database. Previously, I would have had to request a username and password from my database administrator and embed those credentials in environment variables or, in my race to production, even in the application itself. I would also need to have our social media manager create the Twitter API credentials and figure out how to store those. This is a fairly manual process, involving multiple people, that I have to restart every time I want to rotate these credentials. With Secrets Manager my database administrator can provide the credentials in secrets manager once and subsequently rely on a Secrets Manager provided Lambda function to automatically update and rotate those credentials. My social media manager can put the Twitter API keys in Secrets Manager which I can then access with a simple API call and I can even rotate these programmatically with a custom lambda function calling out to the Twitter API. My secrets are encrypted with the KMS key of my choice, and each of these administrators can explicitly grant access to these secrets with with granular IAM policies for individual roles or users.

Let’s take a look at how I would store a secret using the AWS Secrets Manager console. First, I’ll click Store a new secret to get to the new secrets wizard. For my RDS Aurora instance it’s straightforward to simply select the instance and provide the initial username and password to connect to the database.

Next, I’ll fill in a quick description and a name to access my secret by. You can use whatever naming scheme you want here.

Next, we’ll configure rotation to use the Secrets Manager-provided Lambda function to rotate our password every 10 days.

Finally, we’ll review all the details and check out our sample code for storing and retrieving our secret!

Finally I can review the secrets in the console.

Now, if I needed to access these secrets I’d simply call the API.

import json
import boto3
import json
secrets = boto3.client("secretsmanager")
rds = json.dumps(secrets.get_secret_value(SecretId="prod/TwitterApp/Database")['SecretString'])
print(rds)

Which would give me the following values:

{'engine': 'mysql',
 'host': 'twitterapp2.abcdefg.us-east-1.rds.amazonaws.com',
 'password': '-)Kw>THISISAFAKEPASSWORD:lg{&sad+Canr',
 'port': 3306,
 'username': 'ranman'}

More than passwords

AWS Secrets Manager works for more than just passwords. I can store OAuth credentials, binary data, and more. Let’s look at storing my Twitter OAuth application keys.

Now, I can define the rotation for these third-party OAuth credentials with a custom AWS Lambda function that can call out to Twitter whenever we need to rotate our credentials.

Custom Rotation

One of the niftiest features of AWS Secrets Manager is custom AWS Lambda functions for credential rotation. This allows you to define completely custom workflows for credentials. Secrets Manager will call your lambda with a payload that includes a Step which specifies which step of the rotation you’re in, a SecretId which specifies which secret the rotation is for, and importantly a ClientRequestToken which is used to ensure idempotency in any changes to the underlying secret.

When you’re rotating secrets you go through a few different steps:

1. createSecret
2. setSecret
3. testSecret
4. finishSecret

The advantage of these steps is that you can add any kind of approval steps you want for each phase of the rotation. For more details on custom rotation check out the documentation.

Available Now
AWS Secrets Manager is available today in US East (N. Virginia), US East (Ohio), US West (N. California), US West (Oregon), Asia Pacific (Mumbai), Asia Pacific (Seoul), Asia Pacific (Singapore), Asia Pacific (Sydney), Asia Pacific (Tokyo), Canada (Central), EU (Frankfurt), EU (Ireland), EU (London), and South America (São Paulo). Secrets are priced at $0.40 per month per secret and $0.05 per 10,000 API calls. I’m looking forward to seeing more users adopt rotating credentials to secure their applications!

– Randall