Let's Hack a Pipeline: Stealing Another Repo

Details an attack vector where a malicious user can leverage pipeline definitions to clone and push code from unauthorized repositories using the build service identity's elevated privileges. Explains the history of build service identity scoping and the power of editing pipeline definitions. Introduces two mitigation strategies: 'Limit job authorization scope' to project level and explicitly defining repository access in the 'resources' section of the pipeline, requiring one-time authorization for new repositories.