How to secure our AWS accounts

When we think about cloud computing, flexibility and scalability often come to mind. But there’s another important aspect to it, which is security. As powerful as AWS is, a poorly secured account can quickly become a liability due to data breaches, unauthorized access, and surprise bills. AWS offers a suite of tools and best practices to help us secure our accounts and stay ahead of threats.

Let’s walk through the best practices to secure the AWS account.

1. Start with IAM: Granular access & least privilege

Identity and Access Management (IAM) is our first line of defense. Instead of using the root account for day-to-day operations, create individual IAM users and assign them fine-grained permissions. This approach is commonly referred to as the Principle of Least Privilege, which suggests giving users just enough access to do their job, and nothing more.

Better yet, group users with similar responsibilities and assign permissions to the IAM user group, not individually. An IAM user group allows us to apply policies at scale making it easier to manage, audit, and adjust.

For instance, a data science team might need access to services like Amazon SageMaker and Amazon Redshift, while a development team may only require permissions for AWS compute services such as EC2 and Lambda. Group-based permissions make it easy to align access with team roles and scale securely as the organization grows.

Another way to grant granular access is IAM Roles. They are crucial when we need to delegate permissions securely, whether between services or accounts. For example, if an EC2 instance needs to access S3, assign it a role with S3 permissions instead of embedding credentials. One key advantage of IAM roles is that they can be assigned or revoked with ease.

2. Enable Multi-Factor Authentication (MFA)

Multi-factor authentication requires two or more authentication methods, adding an extra layer of security. Enable it for all privileged users, especially the root user. It drastically reduces the risk of unauthorized access, even if someone gets hold of a password.

3. Encrypt everything

Make sure all the data, either at rest or in transit is encrypted. Storage services like S3 and RDS offer built in mechanisms to support data encryption which makes the entire process manifolds easier.

Additionally, AWS offers built-in KMS (Key Management Service), which lets us manage keys centrally and audit their usage. According to AWS shared responsibility model, data encryption falls under the user's responsibility, thus it is necessary to effectively utilise these features.

4. Monitor with AWS CloudTrail

It is difficult to secure an account if we don't know who did what, when, and from where. CloudTrail automatically records every API call in the AWS account and offers complete visibility into the account.This includes actions like launching an EC2 instance, updating a security group, deleting an S3 bucket, or even a failed login attempt.

We can configure CloudTrail to deliver logs to Amazon S3 for long-term storage and auditing, For operational insight and immediate response, these logs can also be sent to Amazon CloudWatch Logs, where you can set up metric filters and alarms to alert on suspicious or unauthorized behavior.

By enabling CloudTrail across all regions and creating organization wide trails in AWS Organizations, we ensure consistent monitoring and governance, even in accounts we don’t manage day to day.

5. Utilize AWS security services

While IAM and CloudTrail lay the foundation, AWS offers advanced security services to help us proactively detect, and respond to threats in the AWS environment, such as AWS Macie, GuardDuty and Inspector.

• Inspector analyzes EC2 instances for vulnerabilities including unpatched software or exposed ports.

• GuardDuty uses machine learning to detect suspicious activity, like brute-force attempts or unusual API usage.

• AWS Macie uses machine learning and pattern matching to automatically discover, classify, and protect data like personally identifiable information (PII) or financial records in S3.

Both services integrate seamlessly with CloudTrail, enriching your logs and alerts with intelligent context. It’s like adding smart surveillance to your digital perimeter.

7. Billing and budget protection

In AWS costs can spiral if resources are misused. Use AWS Budgets to define thresholds for expected usage or spending. Set billing alarms with CloudWatch, to generate an alert the moment costs go out of bounds. It’s one of the fastest ways to detect unintended or malicious activity.

Conclusion

AWS security isn’t just a one-time setup but an ongoing process of least privilege, layered protection, and constant monitoring. Start small, apply the principles above, and utilize AWS’s powerful toolset.

If you have just created an AWS account and want to secure it, here's a quick checklist:

• Disable root access for daily use

• Create IAM users with least privilege

• Enable MFA for all users

• Use roles for service access

• Encrypt data at rest and in transit

• Monitor all activity with CloudTrail

• Integrate GuardDuty and Inspector

• Set AWS Budgets and billing alarms

• Use CloudWatch for system-level alerts