AWS EC2 with Over-Permissive IAM Role

Description:

AWS EC2 instances can be associated with IAM roles to allow the applications or services running on them to interact with other AWS services. An over-permissive IAM role can provide broader access than necessary, which poses a security risk. It allows potential attackers to leverage the excess permissions for malicious actions, such as data exfiltration, resource modifications, or privilege escalation.

Remediation:

1. Restrict IAM Role Permissions:

Limit the permissions granted to EC2 instances to only those that are necessary for their intended function.

AWS Management Console:

• Navigate to the IAM Dashboard.
• Click on Roles and select the over-permissive role associated with your EC2 instance.
• Under the Permissions tab, modify the attached policies to remove any unnecessary permissions or attach more restrictive policies.

AWS CLI:

To detach an over-permissive policy and attach a more restrictive one:

aws iam detach-role-policy --role-name [ROLE_NAME] --policy-arn [OVER_PERMISSIVE_POLICY_ARN]
aws iam attach-role-policy --role-name [ROLE_NAME] --policy-arn [RESTRICTIVE_POLICY_ARN]

Terraform:

To define a more restrictive IAM policy for an EC2 instance:

resource "aws_iam_role" "restricted_role" {
  # ... other configurations ...

  assume_role_policy = # JSON policy defining which entities can assume this role
}

resource "aws_iam_role_policy" "restrictive_policy" {
  role   = aws_iam_role.restricted_role.name
  policy = # JSON policy defining restricted permissions
}

resource "aws_instance" "example" {
  # ... other configurations ...

  iam_instance_profile = aws_iam_instance_profile.example.name
}

Recommendation:

Always adhere to the principle of least privilege when configuring IAM roles for EC2 instances. This ensures that EC2 instances have only the permissions they need to operate correctly. Regularly review IAM policies associated with EC2 instances to identify and rectify overly permissive configurations. By doing this, you reduce the potential impact of a compromised instance or application.