US Patent 10193918 Behavior-based ransomware detection using decoy files

An anti-malware application analyzes behavior of an executing process to identify ransomware. The anti-malware application detects an untrusted process requesting enumeration of a directory of user files and causes the untrusted process to initially operate on a decoy file that mimics the user files. If the behavior of the untrusted process with respect to the decoy file is indicative of ransomware, the process can be terminated without loss of the user files. The decoy file may be deployed in a way that is undetectable to the user.