How to manage multiple IAM users on a single EC2 instance? - amazon-web-services

For different AWS services, I need different IAM users to secure the access control. Sometimes, I even need to use different IAM user credentials within a single project in a EC2 instance. What's the proper way to manage this and how I can deploy/attach these IAM user credentials to a single EC2 instance?

While I fully agree with accepted answer that using static credentials is one way of solving this problem, I would like to suggest some improvements over it (and proposed Secrets Manager).
What I would advise as architectural step forward to achieve full isolation of credentials, having them dynamic, and not stored in central place (Secrets Manager proposed above) is dockerizing application and running on AWS Elastic Container Service (ECS). This way you can assign different IAM role to different ECS Tasks.
Benefits over Secrets Manager solution
- use case of someone tampering with credentials in Secrets Manager is fully avoided, as credentials are of dynamic nature (temporary, and automatically assumed through SDKs)
Credentials are managed on AWS side for you
Only ECS Service can assume this IAM role, meaning you can't have actual person stealing the credentials, or developer connecting to production environment from his local machine with this credentials.
AWS Official Documentation for Task Roles

The normal way to provide credentials to applications running on an Amazon EC2 instance is to assign an IAM Role to the instance. Temporary credentials associated with the role when then be provided via Instance Metadata. The AWS SDKs will automatically use these credentials.
However, this only works for one set of credentials. If you wish to use more than one credential, you will need to provide the credentials in a credentials file.
The AWS credentials file can contain multiple profiles, eg:
[default]
aws_access_key_id = AKIAaaaaa
aws_secret_access_key = abcdefg
[user2]
aws_access_key_id = AKIAbbbb
aws_secret_access_key = xyzzzy
As a convenience, this can also be configured via the AWS CLI:
$ aws configure --profile user2
AWS Access Key ID [None]: AKIAbbbb
AWS Secret Access Key [None]: xyzzy
Default region name [None]: us-east-1
Default output format [None]: text
The profile to use can be set via an Environment Variable:
Linux: export AWS_PROFILE="user2"
Windows: set AWS_PROFILE="user2"
Alternatively, when calling AWS services via an SDK, simply specify the Profile to use. Here is an example with Python from Credentials — Boto 3 documentation:
session = boto3.Session(profile_name='user2')
# Any clients created from this session will use credentials
# from the [user2] section of ~/.aws/credentials.
dev_s3_client = session.client('s3')
There is an equivalent capability in the SDKs for other languages, too.

Related

Switch between Accounts when hosted on EC2 Instance

We currently have 2 AWS accounts that we use. For most of the stuff we want to use the AWS account that our web app is hosted on in an EC2 instance so this works fine:
services.AddDefaultAWSOptions(this.Configuration.GetAWSOptions());
services.AddAWSService<IAmazonSQS>();
services.AddAWSService<IAmazonSimpleSystemsManagement>();
However, I want to access EC2 instances in another AWS account. I've configured it to work locally using credentials and from following this guide (where it mentions about using multiple services): https://docs.aws.amazon.com/sdk-for-net/latest/developer-guide/net-dg-config-netcore.html
services.AddDefaultAWSOptions(this.Configuration.GetAWSOptions());
services.AddAWSService<IAmazonSQS>();
services.AddAWSService<IAmazonSimpleSystemsManagement>();
if (this.WebHostEnvironment.IsDevelopment())
{
// This works fine locally, but I don't want to use credential file in production
var other = this.Configuration.GetAWSOptions("other");
services.AddAWSService<IAmazonEC2>(other);
}
else
{
// How do I register other here without putting a credential file on my ec2 instance?
services.AddAWSService<IAmazonEC2>();
}
I'm not sure how to register IAmazonEC2 to use my other account. I don't want to put a credential file on my instance which is how I get it working locally but it doesn't seem right to me on production servers.
I have configured an IAM role that has access to my other account and given it to my EC2 instance. But how do I translate that IAM role to a profile to use where I am registering IAmazonEC2 above?
Any help appreciated. Thanks
There are really two ways to do it...
Option 1: Use an IAM Role
Let's say that the Amazon EC2 instance is running in Account-A and it now wants to query information about Account-B. You could:
Create an IAM Role in Account-B, with a trust policy that trusts the IAM Role being used by the EC2 instance in Account-A
Your code running on the EC2 instance in Account-A can call AssumeRole() (using the normal credentials from Account-A). This will return a set of temporary credentials.
Use those temporary credentials to make API calls to Account-B
Option 2: Use credentials from Account-B
Alternatively, give your program a set of IAM User credentials from Account-B. These could be stored in AWS Systems Manager Parameter Store - AWS Systems Manager or AWS Secrets Manager, and retrieved by using the normal credentials assigned to the EC2 instance in Account-A.

Hiding Secret Keys in SageMaker (Environment Variables?)

I used to hide connection credentials in environmental variables (.bash_profile). Recently working with SageMaker, I tried a similar process with the terminal available in SageMaker but I am getting the following error,
NameError: name 'DB_USER' is not defined
Is there any efficient way to hide the credentials in SageMaker?
the recommended way to handle secret storage within AWS is AWS Secrets Manager. Secrets Manager stores secret in a secured fashion as a key-value pair. The key benefit is that it allows you to administer access to those secrets via IAM roles and permission abstractions, and retrieve them with the SDK of your choice, such as boto3 for example. Secrets Manager is actually also used by Amazon SageMaker for git credential storage in the case of third-party git integrations
Extending on Olivier's answers, you could provide your Sagemaker endpoint with the proper roles in the deployment code like so
role = 'arn:aws:iam::xxxxxxxxxx:role/service-role/AmazonSageMaker-ExecutionRole-xxxxxxxxxx:role'
sagemaker_model = MXNetModel(model_data = 's3://' + bucket + '/model/model.tar.gz',
role = role,
entry_point = 'entry_point.py',
py_version='py3',
framework_version='1.4.1',
sagemaker_session = sagemaker_session)
Just remember to provide the necessary permissions in the Role you provided

Get secrets from AWS Secret manager without passing access key and secret key from config

I am using AWS Secret Manager Service to retrieve some confidential information like SMTP details or connection strings. However, to get secret value from AWS Secret Manager Service it seems like we need to pass the Access key and secret key apart from which secret we want to retrieve. So I am maintaining those values in config file.
public AwsSecretManagerService(IOptions<AwsAppSettings> settings)
{
awsAppSettings = settings.Value;
amazonSecretsManagerClient = new AmazonSecretsManagerClient
(awsAppSettings.Accesskey, awsAppSettings.SecretKey, RegionEndpoint.GetBySystemName(awsAppSettings.Region));
}
public async Task<SecretValueResponse> GetSecretValueAsync(SecretValueRequest secretValueRequest)
{
return _mapper.Map<SecretValueResponse>(await amazonSecretsManagerClient.GetSecretValueAsync(_mapper.Map<GetSecretValueRequest>(secretValueRequest)));
}
So I am thinking I am kind of defeating the whole purpose of using secret manager by maintaining the AWS credentials in app settings file. I am wondering what is the right way to do this
It is not a good practice to pass or add AWS credentials of an IAM User (access key and secret access key) in the code.
Instead, don't pass it and update your code as follows:
amazonSecretsManagerClient = new AmazonSecretsManagerClient
(RegionEndpoint.GetBySystemName(awsAppSettings.Region));
Question: Then how would it access the AWS services?
Answer: If you are going to execute your code on your local system, install and configure AWS CLI instead of passing AWS credentials via CLI or Terminal, it will use those AWS configured credentials to access the AWS services.
Reference for AWS CLI Installation: Installing the AWS CLI
Reference for AWS CLI Configuration: Configuring the AWS CLI
If you are going to execute your code on an AWS service (e.g., EC2 instance), attach an IAM role with that AWS resource (e.g., EC2 instance) having sufficient permissions, it will use that IAM role to access the AWS services.

Does my application need to ask for a role on ec2 instance to configure the session or leave it empty?

I'm trying to use the aws-sdk-go in my application. It's running on EC2 instance. Now in the Configuring Credentials of the doc,https://docs.aws.amazon.com/sdk-for-go/api/, it says it will look in
*Environment Credentials - Set of environment variables that are useful when sub processes are created for specific roles.
* Shared Credentials file (~/.aws/credentials) - This file stores your credentials based on a profile name and is useful for local development.
*EC2 Instance Role Credentials - Use EC2 Instance Role to assign credentials to application running on an EC2 instance. This removes the need to manage credential files in production.`
Wouldn't the best order be the reverse order? But my main question is do I need to ask the instance if it has a role and then use that to set up the credentials if it has a role? This is where I'm not sure of what I need to do and how.
I did try a simple test of creating a empty config with essentially only setting the region and running it on the instance with the role and it seems to have "worked" but in this case, I am not sure if I need to explicitly set the role or not.
awsSDK.Config{
Region: awsSDK.String(a.region),
MaxRetries: awsSDK.Int(maxRetries),
HTTPClient: http.DefaultClient,
}
I just want to confirm is this the proper way of doing it or not. My thinking is I need to do something like the following
role = use sdk call to get role on machine
set awsSDK.Config { Credentials: credentials form of role,
...
}
issue service command with returned client.
Any more docs/pointers would be great!
I have never used the go SDK, but the AWS SDKs I used automatically use the EC2 instance role if credentials are not found from any other source.
Here's an AWS blog post explaining the approach AWS SDKs follow when fetching credentials: https://aws.amazon.com/blogs/security/a-new-and-standardized-way-to-manage-credentials-in-the-aws-sdks/. In particular, see this:
If you use code like this, the SDKs look for the credentials in this
order:
In environment variables. (Not the .NET SDK, as noted earlier.)
In the central credentials file (~/.aws/credentials or
%USERPROFILE%.awscredentials).
In an existing default, SDK-specific
configuration file, if one exists. This would be the case if you had
been using the SDK before these changes were made.
For the .NET SDK, in the SDK Store, if it exists.
If the code is running on an EC2
instance, via an IAM role for Amazon EC2. In that case, the code gets
temporary security credentials from the instance metadata service; the
credentials have the permissions derived from the role that is
associated with the instance.
In my apps, when I need to connect to AWS resources, I tend to use an access key and secret key that have specific predefined IAM roles. Assuming I have those two, the code I use to create a session is:
awsCredentials := credentials.NewStaticCredentials(awsAccessKeyID, awsSecretAccessKey, "")
awsSession = session.Must(session.NewSession(&aws.Config{
Credentials: awsCredentials,
Region: aws.String(awsRegion),
}))
When I use this, the two keys are usually specified as either environment variables (if I deploy to a docker container).
A complete example: https://github.com/retgits/flogo-components/blob/master/activity/amazons3/activity.go

Mounting AWS S3 bucket using AWS IAM roles instead of using a passwd file

I am mounting an AWS S3 bucket as a filesystem using s3fs-fuse. It requires a file which contains AWS Access Key Id and AWS Secret Access Key.
How do I avoid the access using this file? And instead use AWS IAM roles?
As per Fuse Over Amazon document, you can specify the credentials using 4 methods. If you don't want to use a file, then you can set AWSACCESSKEYID and AWSSECRETACCESSKEY environment variables.
Also, if your goal is to use AWS IAM instance profile, then you need to run your s3fs-fuse from an EC2 instance. In that case, you don't have to set these credential files/environment variables. This is because while creating the instance, if you attach the instance role and policy, the EC2 instance will get the credentials at boot time. Please see the section 'Using Instance Profiles' in page 190 of AWS IAM User Guide
there is an argument -o iam_role=--- which helps you to avoid AccessKey and SecretAccessKey
The Full steps to configure this is given below
https://www.nxtcloud.io/mount-s3-bucket-on-ec2-using-s3fs-and-iam-role/