action: sts:AssumeRole (aws iam role)

sts:AssumeRole
sts:AssumeRoleWithWebIdentity

Official example

https://aws.amazon.com/blogs/security/how-to-use-trust-policies-with-iam-roles/

{
 "Version": "2012-10-17",
 "Statement": [
   {
     "Effect": "Allow",
     "Principal": {
       "AWS": "arn:aws:iam::111122223333:root"
     },
     "Action": "sts:AssumeRole"
   }
 ]
}

Examples

Access to s3:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "Service": "s3.amazonaws.com"
            },
            "Action": "sts:AssumeRole"
        }
    ]
}

Access to s3 and one more cross-account role:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "Service": "s3.amazonaws.com"
            },
            "Action": "sts:AssumeRole"
        },
        {
            "Effect": "Allow",
            "Principal": {
                "AWS": "arn:aws:iam::01234567890:role/your-role",
                "AWS": "arn:aws:iam::11111111111:role/your-other-role"
            },
            "Action": "sts:AssumeRole"
        }
    ]
}

• How can I pass secrets or sensitive information securely to containers in an Amazon ECS task?

 {
 "Version": "2012-10-17",
 "Statement": [
   {
     "Sid": "",
     "Effect": "Allow",
     "Principal": {
       "Service": "ecs-tasks.amazonaws.com"
     },
     "Action": "sts:AssumeRole"
   }
 ]
}

 resource "aws_iam_role" "ecs_task_role" {
 name               = "your-ecs-task-role"
 assume_role_policy = <<-EOF
 {
   "Version": "2012-10-17",
   "Statement": [
     {
       "Sid": "",
       "Effect": "Allow",
       "Principal": {
         "Service": "ecs-tasks.amazonaws.com"
       },
       "Action": [
         "sts:AssumeRole"
       ]
     }
   ]
 }
 EOF
}

 resource "aws_iam_role" "test_role" {
 name = "test_role"

 # Terraform's "jsonencode" function converts a
 # Terraform expression result to valid JSON syntax.
 assume_role_policy = jsonencode({
   Version = "2012-10-17"
   Statement = [
     {
       Action = "sts:AssumeRole"
       Effect = "Allow"
       Sid    = ""
       Principal = {
         Service = "ec2.amazonaws.com"
       }
     },
   ]
 })

 tags = {
   tag-key = "tag-value"
 }
}

Related

• aws sts assume-role
• aws iam add-role-to-instance-profile
• Amazon Cloudformation EKS cluster role
• An error occurred (ValidationError) when calling the AssumeRole operation:
• aws sts get-caller-identity
• sts:
• aws ssm put-parameter
• aws iam list-instance-profiles
• Terraform resource: aws_iam_role
• sts:AssumeRoleWithWebIdentity

See also

• AWS STS (sts:), aws sts [ get-session-token | get-caller-identity | assume-role | assume-role-with-web-identity | assume-role-with-saml | get-access-key-info ]
• AWS IAM role, ServiceRoleARN, iam:GetRole, assumed-role, sts:AssumeRole, Trusted entities