Computer security method and system with input parameter validation

A security system, including a receiver for receiving a downloadable, a scanner, coupled with the receiver, for scanning the downloadable to identify suspicious computer operations therein, a code modifier, coupled with the scanner, for overwriting the suspicious computer operations with substitute computer operations, if at least one suspicious computer operation is identified by the scanner, and for appending monitoring program code to the downloadable thereby generating a modified downloadable, if at least one suspicious computer operation is identified by the scanner, and a processor, coupled with the code modifier, for executing programmed instructions, wherein the monitoring program code includes program instructions for the processor to validate input parameters for the suspicious computer operations during run-time of the downloadable. A method is also described and claimed.