BOM stands for bill of materials: the complete parts list used to build a product. In engineering, it can include components, part numbers, suppliers, quantities, revisions, and sometimes software or firmware dependencies. A BOM is not just administrative paperwork; it is a core record of how a system is assembled and maintained.
In cyber security, BOMs matter because they can reveal valuable technical and supply-chain intelligence. An exposed BOM may help an attacker identify target components, map dependencies, find alternative suppliers, or infer manufacturing and design priorities. For defenders, BOMs are useful for inventory, patching, and vulnerability response because they show what is actually in a product. Security teams often protect BOMs alongside CAD files, test data, and source code, since together these files can enable theft, impersonation, or targeted extortion.