Cross-service confused deputy prevention
The confused deputy problem is a security issue where an entity that doesn't have permission to perform an action can coerce a more-privileged entity to perform the action. In Amazon, cross-service impersonation can result in the confused deputy problem. Cross-service impersonation can occur when one service (the calling service) calls another service (the called service). The calling service can be manipulated to use its permissions to act on another customer's resources in a way it should not otherwise have permission to access. To prevent this, Amazon provides tools that help you protect your data for all services with service principals that have been given access to resources in your account.
We recommend using the aws:SourceArn
and aws:SourceAccount
global condition context keys in resource
policies to limit the permissions that Amazon Batch gives another service to the
resource. If the aws:SourceArn
value does not contain the account ID, such as
an Amazon S3 bucket ARN, you must use both global condition context keys to limit permissions. If
you use both global condition context keys and the aws:SourceArn
value contains
the account ID, the aws:SourceAccount
value and the account in the
aws:SourceArn
value must use the same account ID when used in the same
policy statement. Use aws:SourceArn
if you want only one resource to be
associated with the cross-service access. Use aws:SourceAccount
if you want to
allow any resource in that account to be associated with the cross-service use.
The value of aws:SourceArn
must be the resource that Amazon Batch stores.
The most effective way to protect against the confused deputy problem is to use the aws:SourceArn
global condition context key with the full ARN of the resource. If you don't know the full ARN of the resource or if
you are specifying multiple resources, use the aws:SourceArn
global context condition key with wildcard
characters (*
) for the unknown portions of the ARN. For example,
arn:aws-cn:
.servicename
:*:123456789012
:*
The following examples shows how you can use the aws:SourceArn
and aws:SourceAccount
global condition context keys in Amazon Batch to prevent the confused deputy problem.
Example: Role for accessing only one compute environment
The following role can only be used to access one compute environment. The job name must be specified as
because the job queue can be associated with multiple compute
environments.*
{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "Service": "batch.amazonaws.com" }, "Action": "sts:AssumeRole", "Condition": { "StringEquals": { "aws:SourceAccount": "
123456789012
" }, "ArnLike": { "aws:SourceArn": [ "arn:aws-cn:batch:us-east-1
:123456789012
:compute-environment/testCE
", "arn:aws-cn:batch:us-east-1
:123456789012
:job/*
" ] } } } ] }
Example: Role for accessing multiple compute environments
The following role can be used to access multiple compute environments. The job name must be specified as
because the job queue can be associated with multiple compute
environments.*
{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "Service": "batch.amazonaws.com" }, "Action": "sts:AssumeRole", "Condition": { "StringEquals": { "aws:SourceAccount": "
123456789012
" }, "ArnLike": { "aws:SourceArn": [ "arn:aws-cn:batch:us-east-1
:123456789012
:compute-environment/*
", "arn:aws-cn:batch:us-east-1
:123456789012
:job/*
" ] } } } ] }