A computing device includes a central processing resource, memory, a network interface, and a security control module. The security control module determines when to change a program of the computing device. When the program is to be changed, the security control module accesses a library of programs that includes a plurality of versions of the program and selects one of the plurality of versions of the program. The security control module then updates an active program list to include the selected version of the program. When the program is evoked, the central processing resource uses the selected version of the program such that execution of the program is changed, which changes internal operation of the computing device thereby reducing adverse impact of the malicious software.