It is a lot of work to ensure that an open source project runs the correctly on all of its supported platforms. Fortunately, there are a growing number of cloud-based services that offer to remove this tedium, and for free! They will download, compile, and execute your code and let you know if everything goes as planned. This presentation will explore attack scenarios that could happen if malicious source code is fed into these services and provides perspective, advice and a new tool to help defend them from compromise.