awssecurity iam, best_practices

When you create a new AWS account you are the root user who has unlimited access to everything. Using such a powerful user as root on a day-to-day basis is not such a good idea because if it gets compromised you may not have a way to override and/or undo the changes done by the hacker.

Using IAM user instead of root account

Instead, suggested best practice is to create an admin-level IAM account and use it for normal operations. At first I was hesitant to adopt this practice. I didn’t see the point and thought attaching AdministratorAccess policy awould make the use as powerful as root. But there’s a whole list of things that even the most powerful IAM user cannot do. Here’s the list: AWS Tasks That Require AWS Account Root User Credentials

So as you can see root user has important privileges such as closing the account and changing billing information. Even if your account gets compromised and some mailicous person gains access using an IAM account, you can still log in as root and take necessary action.

In a nutshell, based on AWS documentation the following practices are recommended:

  • Use the root user only to create your first IAM user
  • Create an IAM user for yourself as well, give that user administrative permissions, and use that IAM user for all your work.

In addition to Eric Hammond suggests in his blog to delete the root account password as well and use Forgot Password option to create a new one when needed. I keep my passwords in a password manager so if that application is compromised, the hacker can reset my password as well so I don’t follow this practice but it might come in handy if you have to write your password down somewhere.

Templated IAM user creation

It’s a good practice to create an IAM user right after you create your AWS account. It’s even a better practice to automate this process. To achieve this I created a CloudFormation template. The YAML template below does the following:

  • Creates an IAM group named administrators
  • Creates a user named admin
  • Attaches AdministratorAccess policy to the group
  • Forces the user to change their password first time they log in (by attaching IAMUserChangePassword policy to the user)
Resources:
  AdministratorsGroup:
    Type: AWS::IAM::Group
    Properties:
      GroupName: "administrators"
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/AdministratorAccess
      Path: /

  AdminUser:
    Type: AWS::IAM::User
    Properties: 
      Groups:
        - !Ref AdministratorsGroup
      LoginProfile:
        Password: "CHANGE_THIS"
        PasswordResetRequired: true
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/IAMUserChangePassword
      Path: /
      UserName: "admin"

Resources

awsdevops cloudformation

If you have a habit creating your AWS resources manually, things can get very messy very quickly. At some point you realize that you have no idea if a resource is still in use and just to be safe you leave it alone.

I found myself in this situation and decided to take advantage Infrastructure as Code paradigm using AWS CloudFormation. To start simple I decided to migrate my automated CV response application to a CloudFormation stack. Going forward this is a much efficient way to write blog posts too. Instead of writing step by step instructions I can simply post the CloudFormation stack in JSON or YAML.

Infrastructure of Code in a nutshell

Basically this approach allows you to define, manage and provision all the resources that define your system.

Advantages:

  • Changes can be source-controlled
  • Entire provisioning process can be automated
  • entire infrastructure can be easily recreated in a different account.
  • Resources can easily be identified. Tags can be used to identify which stack the resources belong to.
  • Resources can easily be clean up. Deleting a stack will delete all the resource it created.

Basic Terminology

  • Stack: All the resources used to create an infrastructure.
  • StackSet: A StackSet is a container for AWS CloudFormation stacks that lets you provision stacks across AWS accounts and regions by using a single AWS CloudFormation template.
  • Design template: This is the file YAML or JSON format that defines all the resources that will be created AWS

Where to start…

Even though you get familiar with the concepts finding where tostart can be intimidating sometimes. When it comes to CloudFormation, there are a lot of sample templates that you can start and build upon.

So here’s an easy way to get started:

Step 1: Save the following snippet to a local file such as cloudformation.sample.yaml:

Resources:
  Ec2Instance:
    Type: AWS::EC2::Instance
    Properties:
      InstanceType: t2.micro
      ImageId: ami-0aff88ed576e63e90

In the example above I’m using a stock AWS Linux AMI in London region.

Step 2: Go to Stack and click Create Stack (Make sure you’re in EU London region otherwise AWS won’t be able to find the AMI specified in our template)

Step 3: In specify template section, select Upload a template file

Step 4: Clock Choose file to locate your file and upload your template.

Step 5: Click next and specify a stack name something like FirstStackForEC2 and click Next

Step 6: Click Next on Configure Stack Options view and in the final review step of the wizard click Create Stack.

At this point you can observe the progress of your stack being created.

Now if you go to EC2 service in the same region you should be able to see the new instance:

If you delete the stack, it will in turn delete everything it created which is the EC2 instance in this example.

Launch Stack URLs

I always like the launch stack buttons that I see every now and then. I think there’s something magical about clicking a button and watching an entire infrastructure being created right before your eyes!

Basically clicking the Launch Stack URL opens the wizard we just used with the fields populated with the values in the template.

Step 1: Upload the template to S3 and make it publicly accessible.

Step 2: Use the following naming convention and replace the values:

https://console.aws.amazon.com/cloudformation/home?region=region#/stacks/new?stackName=stack_name&templateURL=template_location

In this example I uploaded the Launch Stack button image to my GitHub repository so that I can link to it.

Resources

aws aurora, rds, serverless, database

A few months ago AWS announced a serverless model for their Aurora databases. Compared to traditional DB approach this is brand new.

I’ve been trying it out for a pilot application and it works well in general. You pay for what you use just like any other serverless resource.

The only problem I’ve been having is DB startup time after pause. Meaning after 5 minutes the resources are released and the first request that comes after that suffers a performance penalty. My application was getting an error when this happened and it was showing an error screen. Obviously from a user standpoint it’s not a great experience.

So to remedy this issue I’ve updated the DB connection timeout

Connection Timeout=120

By default it’s 15 seconds which is not enough for the new server to respond. But after increasing the timeout at least I could prevent the application from failing. Of course this doesn’t speed up the response time of the DB server.

They recently announced additional regions that support serverless Aurora.

For cost-cutting reasons this can be a great option. Especially if your system is idle for extended periods of time you don’t need to pay anything. Also it scales up so you don’t have to worry about the database bottlenecks under heavy traffic.

Resources