Database secrets engine

The database secrets engine generates database credentials dynamically based on configured roles. It works with a number of different databases through a plugin interface. There are a number of built-in database types, and an exposed framework for running custom database types for extendability. This means that services that need to access a database no longer need to hardcode credentials: they can request them from Vault, and use Vault's leasing mechanism to more easily roll keys. These are referred to as "dynamic roles" or "dynamic secrets".

Since every service is accessing the database with unique credentials, it makes auditing much easier when questionable data access is discovered. You can track it down to the specific instance of a service based on the SQL username.

Vault makes use of its own internal revocation system to ensure that users become invalid within a reasonable time of the lease expiring.

Static roles

Vault also supports static roles for all database secrets engines. Static roles are a 1-to-1 mapping of Vault roles to usernames in a database. With static roles, Vault stores and automatically rotates passwords for the associated database user based on a configurable period of time or rotation schedule.

When a client requests credentials for the static role, Vault returns the current password for whichever database user is mapped to the requested role. With static roles, anyone with the proper Vault policies can access the associated user account in the database.

Setup

Most secrets engines must be configured in advance before they can perform their functions. These steps are usually completed by an operator or configuration management tool.

1. Enable the database secrets engine:

   $ vault secrets enable database
   Success! Enabled the database secrets engine at: database/
   

   By default, the secrets engine will enable at the name of the engine. To enable the secrets engine at a different path, use the -path argument.

2. Configure Vault with the proper plugin and connection information:

   $ vault write database/config/my-database \
       plugin_name="..." \
       connection_url="..." \
       allowed_roles="..." \
       username="..." \
       password="..." \
   

   It is highly recommended a user within the database is created specifically for Vault to use. This user will be used to manipulate dynamic and static users within the database. This user is called the "root" user within the documentation.

   Vault will use the user specified here to create/update/revoke database credentials. That user must have the appropriate permissions to perform actions upon other database users (create, update credentials, delete, etc.).

   This secrets engine can configure multiple database connections. For details on the specific configuration options, please see the database-specific documentation.

3. After configuring the root user, it is highly recommended you rotate that user's password such that the vault user is not accessible by any users other than Vault itself:

   $ vault write -force database/rotate-root/my-database
   

   When this is done, the password for the user specified in the previous step is no longer accessible. Because of this, it is highly recommended that a user is created specifically for Vault to use to manage database users.

4. Configure a role that maps a name in Vault to a set of creation statements to create the database credential:

   $ vault write database/roles/my-role \
       db_name=my-database \
       creation_statements="..." \
       default_ttl="1h" \
       max_ttl="24h"
   Success! Data written to: database/roles/my-role
   

   The {{username}} and {{password}} fields will be populated by the plugin with dynamically generated values. In some plugins the {{expiration}} field is also supported.

Usage

After the secrets engine is configured and a user/machine has a Vault token with the proper permission, it can generate credentials.

1. Generate a new credential by reading from the /creds endpoint with the name of the role:

   $ vault read database/creds/my-role
   Key                Value
   ---                -----
   lease_id           database/creds/my-role/2f6a614c-4aa2-7b19-24b9-ad944a8d4de6
   lease_duration     1h
   lease_renewable    true
   password           FSREZ1S0kFsZtLat-y94
   username           v-vaultuser-e2978cd0-ugp7iqI2hdlff5hfjylJ-1602537260
   

Database capabilities

As of Vault 1.6, all databases support dynamic roles and static roles. All plugins except MongoDB Atlas support rotating the root user's credentials. MongoDB Atlas cannot support rotating the root user's credentials because it uses a public and private key pair to authenticate.

Custom plugins

This secrets engine allows custom database types to be run through the exposed plugin interface. Please see the custom database plugin for more information.

Credential types

Database systems support a variety of authentication methods and credential types. The database secrets engine supports management of credentials alternative to usernames and passwords. The credential_type and credential_config parameters of dynamic and static roles configure the credential that Vault will generate and make available to database plugins. See the documentation of individual database plugins for the credential types they support and usage examples.

Schedule-based static role rotation

The database secrets engine supports configuring schedule-based automatic credential rotation for static roles with the rotation_schedule field. For example:

$ vault write database/static-roles/my-role \
    db_name=my-database \
    username="vault" \
    rotation_schedule="0 * * * SAT"

This configuration will set the role's credential rotation to occur on Saturday at 00:00.

Additionally, this schedule-based approach allows for optionally configuring a rotation_window in which the automatic rotation is allowed to occur. For example:

$ vault write database/static-roles/my-role \
    db_name=my-database \
    username="vault" \
    rotation_window="1h" \
    rotation_schedule="0 * * * SAT"

This configuration will set rotations to occur on Saturday at 00:00. The 1 hour rotation_window will prevent the rotation from occuring after 01:00. If the static role's credential is not rotated during this window, due to a failure or otherwise, it will not be rotated until the next scheduled rotation.

Password generation

Passwords are generated via Password Policies. Databases can optionally set a password policy for use across all roles or at the individual role level for that database. For example, each time you call vault write database/config/my-database you can specify a password policy for all roles using my-database. Each database has a default password policy defined as: 20 characters with at least 1 uppercase character, at least 1 lowercase character, at least 1 number, and at least 1 dash character.

The default password generation can be represented as the following password policy:

length = 20

rule "charset" {
    charset = "abcdefghijklmnopqrstuvwxyz"
    min-chars = 1
}
rule "charset" {
    charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    min-chars = 1
}
rule "charset" {
    charset = "0123456789"
    min-chars = 1
}
rule "charset" {
    charset = "-"
    min-chars = 1
}

Disable character escaping

As of Vault 1.10, you can now specify the option disable_escaping with a value of true in some secrets engines to prevent Vault from escaping special characters in the username and password fields. This is necessary for some alternate connection string formats, such as ADO with MSSQL or Azure SQL. See the databases secrets engine API docs and reference individual plugin documentation to determine support for this parameter.

For example, when the password contains URL-escaped characters like # or % they will remain as so instead of becoming %23 and %25 respectively.

$ vault write database/config/my-mssql-database \
plugin_name="mssql-database-plugin" \
connection_url='server=localhost;port=1433;user id={{username}};password={{password}};database=mydb;' \
username="root" \
password='your#StrongPassword%' \
disable_escaping="true"

Unsupported databases

AWS DynamoDB

Amazon Web Services (AWS) DynamoDB is a fully managed, serverless, key-value NoSQL database service. While DynamoDB is not supported by the database secrets engine, you can use the AWS secrets engine to provision dynamic credentials capable of accessing DynamoDB.

1. Verify you have the AWS secrets engine enabled and configured.

2. Create a role with the necessary permissions for your users to access DynamoDB. For example:

   $ vault write aws/roles/aws-dynamodb-read \
           credential_type=iam_user \
           policy_document=-<<EOF
   {
       "Version": "2012-10-17",
       "Statement": [
           {
               "Effect": "Allow",
               "Action": [
                   "dynamodb:DescribeTable",
                   "dynamodb:GetItem",
                   "dynamodb:GetRecords"
               ],
               "Resource": "arn:aws:dynamodb:us-east-1:1234567891:table/example-table"
           },
           {
               "Effect": "Allow",
               "Action": "dynamodb:ListTables",
               "Resource": "*"
           }
       ]
   }
   EOF
   

3. Generate dynamic credentials for DynamoDB using the aws-dynamodb-read role:

   $ vault read aws/creds/aws-dynamodb-read
   Key                Value
   ---                -----
   lease_id           aws/creds/my-role/kbSnl9WSDzOXQerd8GiVh75N.DACNl
   lease_duration     1h
   lease_renewable    true
   access_key         AKALMNOP123456
   secret_key         xY4XhS3AsM3s+R33tCaybsT2XI6BVL+vF+khbbYD
   security_token     <nil>
   

4. Use the dynamic credentials generated by Vault to access DynamoDB. For example, to connect with the the AWS CLI.

   $ aws dynamodb list-tables --region us-east-1
   {
       "TableNames": [
           "example-table"
       ]
   }
   

Tutorial

Refer to the following step-by-step tutorials for more information:

• Secrets as a Service: Dynamic Secrets
• Database Root Credential Rotation

API

The database secrets engine has a full HTTP API. Please see the Database secret secrets engine API for more details.