“ Little by little, one travels far.”
In this chapter, you will learn about common memory residency strategies that computer viruses use to infect other objects on a system or across systems. Depending on the in-memory residency strategy alone, some viruses can become much more virulent than others.
Some of the simpler computer viruses do not actively manifest themselves in computer memory. The very first file infector viruses on the IBM PC, such as Virdem and Vienna, belong to this category. Usually direct-action viruses do not spread fast and do not easily become in the wild.
Direct-action viruses load with the host program into computer memory. ...