Computer virus detection systems and methods

Systems and methods for computer virus detection are presented. In one embodiment; an computer virus detection method includes: receiving an indication of a change to a file; performing a virus analysis process, including executing the changes to the file in a virtual machine and examining results of the executing the changes; and handling the file based upon the virus analysis. The virus analysis can be performed in a system in which the change to the file occurs. Handling the file can include treating the file as potentially infected with a virus based upon the virus analysis. In one exemplary implementation, examining the results includes comparing the results of executing the changes to the file to other results from executing changes to another file, wherein the file is identified as potentially infected with a virus if the examining results indicates the results of executing the changes to the file are similar to results from executing changes to another file. Examining results includes examining behavior resulting from executing the file (e.g., examining system calls, etc.). Outcome of the examining results can be forwarded for utilization in developing virus data sets.