US Patent 11531757 Ransomware detection and mitigation

There is disclosed in one example a computing apparatus, including: a hardware platform including a processor and a memory; a system profile store; and a ransomware detection engine including instructions encoded within the memory to instruct the processor to: detect an operation, by a process, that results in an operation on a file, wherein the operation includes newly creating the file including a file type identifier, or where the file is an existing file, changing a file type identifier for the file; querying the system profile store with a combination of the file type identifier and metadata about the file; based at least in part on the querying, determining that the process is a suspected ransomware attack; and taking a remedial action.