You might need to allow users from another AWS account to access resources in your AWS account. If so, don't share security credentials, such as access keys, between accounts. Instead, use IAM roles. You can define a role 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. To make process of switching profiles (environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY among others) it is handy to use the code provided on this repo.