US Patent 7779472 Application behavior based malware detection

An executable file is loaded into a virtual machine arranged to emulate the instructions of said executable file. The virtual machine keeps track of application programming interfaces (APIs) used by the executable file during emulation. The executable file is scanned to determine names of (APIs) used. Behavior flags are set if certain conditions occur within the executable file. The APIs determined during emulation and during scanning are compared with a set of known behaviors. A match of the APIs and the known behaviors indicates a high risk of malware. A determination of malware being present is based upon any matches and any behavior flags that are set.