Where do they hide?

Viruses can hide in a host of places without being discovered.

Most common hideouts for viruses include:

Web pages are developed in a specific language and may contain elements known as Java applets or ActiveX controls, in which viruses can hide and infect users that visit pages containing these components.
E-mail messages are a favorite hiding place for viruses and they represent an extremely fast way of spreading. These messages can contain attachments that harbor viruses. Simply opening these messages can lead to infection.
The Main memory (RAM). Viruses can hide in the main memory where they wait for a program to be run (a file with an EXE or COM extension ) in order to infect it. This type of virus is known as a resident virus.
Boot sector: The boot sector of a floppy or hard disk contains information on the characteristics and contents of the disk. Some viruses, known as Boot viruses , enter this area as a means of infecting the computer.
Files with macros make a convenient hiding place for viruses. A macro is a small program that forms part of Word documents (with DOC extensions), Excel spreadsheets (with XSL extensions) and PowerPoint presentations ( PPT or PPS extensions). As these macros are programs they can be infected by viruses.

Where do they hide?

Para ampliar esta información, consulte el apartado Técnicas de propagación y camuflaje.