This is a security restriction on application containers running in the Acquia Kubernetes service.

• If you’re downloading a binary, such as composer.phar or acli.phar (which Acquia has already done for you), you can place it in '$HOME/bin'. The bin folder in the CI user’s home directory is already added to $PATH. It works as long as your binary has an execute permissions set.
• To download a package through `apt` or similar, create a Support ticket.