Can't connect to RDS via AWS.RDS.Signer

I'm trying to connect to my MySQL RDS from a Lambda via AWS.RDS.Signer with the following code and fake credentials:

1  const DB_REGION = 'ap-southeast-2a'  2  const DB_HOST = 'dbinstance.ddtev8utygt.ap-southeast-2.rds.amazonaws.com'  3  const DB_PORT = 3306  4  const DB_USER = 'anyuser'  5  const DB_NAME = 'anydb'  6  7  const signerOptions = {  8    region: DB_REGION,  9    hostname: DB_HOST,  10   port: DB_PORT,  11   username: DB_USER  12 }  13  14 const signer = new AWS.RDS.Signer(signerOptions)  15 const token = await signer.getAuthToken()  16   17 const config = {  18   host: DB_HOST,  19   user: DB_USER,  20   password: token, // "Password123"  21   database: DB_NAME,  22   ssl: 'Amazon RDS',  23   authPlugins: {  24     mysql_clear_password: () => () => token  25   }  26 }  

but I always get this error

"Access denied for user 'anyuser'@'172.14.1.12' (using password: NO)"  

I'm not entirely sure if that is needed for the AWS.RDS.Signer but I selected this option of my database:

Password and IAM database authentication  Authenticates using the database password and user credentials through AWS IAM users and roles.   

NOTE: If I swap the password from token to "Password123" on line 20 I can successfully connect to my RDS.

Am I missing something here or does AWS.RDS.Signer only work with RDS Proxy?

By the way: the getAuthToken function gives me something like that (token truncated)

"dbinstance.ddtev8utygt.apsoutheast2.rds.amazonaws.com:3306/Action=connect&DBUser=anyuser&&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAU7VGXF6UCWYZCFEG%2F20210318%2Fap-southeast-2a%2Frds-db%2Faws4_request&X-Amz-Date=20210318T105145Z&X-Amz-Expires=900&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEAsaDmFwLXNvdXRoZWFzdC0yIkgwRgIhAKg8ibwNJ4E3hSOuq7HtDFvqHxmTlpOUk3I6EH2%2B9VdOV3RQ%2F03xiVdvjhEBkHqEXHQ%3D&X-Amz-Signature=749d931f74873e6c2c0d4fec94f0743f42efd5aa95ca0ac0f05c4bef30e3bd4d&X-Amz-SignedHeaders=host"

https://stackoverflow.com/questions/66689521/cant-connect-to-rds-via-aws-rds-signer March 18, 2021 at 06:47PM