1. A method for detection of computer malware by a portable security device connected to a computer, comprising: performing a malware detection experiment by the security device on the computer by simulating a connection to the computer of a simulated data storage device containing a predefined set of data; determining if there are any modifications in the set of data contained in the simulated data storage device after termination of the malware detection experiment; and based on whether there are any modifications in the set of data, determining whether to perform one or more subsequent malware detection experiments by the security device on the computer, wherein each of the one or more subsequent malware detection experiments are configured to simulate a different connection to the computer of a different simulated data storage device containing the predefined set of data.