To help secure AWS resources, AWS recommends the following AWS Identity and Access Management (IAM) service – IAM Best Practices
Root Account -Don’t use & Lock away access keys
Do not use AWS Root account which has full access to all the AWS resources and services including the Billing information.
Permissions associated with your AWS Root account cannot be restricted.
Do not generate the access keys, if not required
If already generated and not needed, delete the access keys.
If access keys needed, rotate (change) the access key regularly
Never share your Root account credentials or access keys, instead create IAM users or Roles to grant granular access
Enable AWS multifactor authentication (MFA) on your AWS account
User – Create individual IAM users
Don’t use your AWS root account credentials to access AWS, and don’t share your credentials with anyone else.
Start by creating an IAM User with Administrator role, which has access to all resources as the Root user except to the account’s security credentials
Create individual users for anyone who needs access to your AWS account and gives each user unique credentials and grant different permissions
Groups – Use groups to assign permissions to IAM users
Instead of defining permissions for individual IAM users, create groups and define the relevant permissions for each group as per the job function, and then associate IAM users to those groups.
Users in an IAM group inherit the permissions assigned to the group and a User can belong to multiple groups
It is much easier to add new users, remove users and modify the permissions of a group of users.
Permission – Grant least privilege
IAM user, by default, is created with no permissions
Users should be granted LEAST PRIVILEGE as required to perform a task.
Starting with minimal permissions and add to the permissions as required to perform the job function is far better than granting access all and trying to then tighten it down
Passwords – Enforce a strong password policy for users
Enforce user to create strong passwords and enforce them to rotate their passwords periodically
Enable a strong password policy to define passwords requirements forcing users to create passwords with requirements like at least one capital letter, one number, how frequently it should be rotated.
MFA – Enable MFA for privileged users
For extra security, Enable MultiFactor Authentication (MFA) for privileged IAM users, who are allowed access to sensitive resources or APIs.
Role – Use roles for applications that run on EC2 instances
Use roles for applications running on EC2 instances instead of creating IAM user and hardcoding the credentials within that application.
Roles do not have a permanent set of credentials associated with it but dynamically provide temporary credentials that are automatically rotated
Hardcoding of credentials can compromise the access and are also hard to rotate. Also, they may pose a problem in the creation of new EC2 instances through AutoScaling and handling credential rotation.
Sharing – Delegate using roles
Allow users from same AWS account, another AWS account, or externally authenticated users (either through any corporate authentication service or through Google, Facebook etc) to use IAM roles to specify the permissions which can then be assumed by them
A role can be defined that specifies what permissions the IAM users in the other account are allowed, and from which AWS accounts the IAM users are allowed to assume the role
Rotation – Rotate credentials regularly
Change your own passwords and access keys regularly and enforce it through a strong password policy. So even if a password or access key is compromised without your knowledge, you limit how long the credentials can be used to access your resources
Access keys allow the creation of 2 active keys at the same time for a user. These can be used to rotate the keys.
Track – Remove unnecessary credentials
Remove IAM user and credentials (that is, passwords and access keys) that are not needed
Use the Credential report that lists all IAM users in the account and status of their various credentials, including passwords, access keys, and MFA devices and usage pattern to figure out what can be removed
Passwords and access keys that have not been used recently might be good candidates for removal.
Conditions – Use policy conditions for extra security
Define conditions under which IAM policies allow access to a resource.
Conditions would help provide finer access control to the AWS services and resources for e.g. access limited to specific IP range or allowing the only encrypted request for uploads to S3 buckets etc.
Auditing – Monitor activity in the AWS account
Enable logging features provided through CloudTrail, S3, CloudFront in AWS to determine the actions users have taken in the account and the resources that were used.
Log files show the time and date of actions, the source IP for an action, which actions failed due to inadequate permissions, and more.
