Stealth Viruses

In order for a virus to spread it must remain undetected. Most viruses, especially the early ones relied on relatively simple tricks to do this. For example making sure the date/time stamp on files was not changed and preventing error messages from being displayed.

Some viruses however use much more sophisticated tricks which are designed to prevent them being detected. For example, some viruses remove them selves from infected files when the file in opened and reinfect when the file is closed.

Such viruses are known a stealth viruses.

Note that any of the other virus types can also be be stealth viruses.