Collateral Appeal Collateral Attack A collateral appeal, also known as a collateral attack, is a legal challenge to a criminal conviction that occurs outside the direct appeal process. Instead of challenging the validity of the conviction based on the record of the original trial (as in a direct appeal), a collateral appeal addresses issues such as newly discovered evidence, ineffective assistance of counsel, or constitutional violations that weren't raised during the trial or on direct appeal. This form of relief is often sought after all direct appeals have been exhausted.