In general, the invention relates to a method for securing a computer system. The method includes monitoring an operating system in the computer system and trapping, in response to the monitoring, a process system call where the process system call originated in a host executing in the computer system. Responsive to the trapping, an isolated user environment (IUE) is created in the computer system. Creating the IUE includes allocating memory and persistent storage for the IUE. In addition, the IUE includes a file system filter driver (FSFD) configured to redirect Input/Output (I/O) calls originating from the IUE to the persistent storage, and a network interface/NDIS hook component configured to control network traffic originating from the IUE and destined for the IUE. The method further includes, after creating the IUE, loading the process system call into the IUE and executing the process system call in the IUE.