Hacking the Hacker

9Malware

When I first started in computer security back in 1987, it was malicious programs (malware) that first caught my eye. The first computer viruses (for example Apple’s Elk Cloner and Pakistani Brain) were just showing up, although Trojans and worms had been around longer. Computer viruses were so unknown and almost rare that popular media pundits declared them to be hoaxes. That was until entire companies were taken down by them, and this was before the Internet was the Internet. Back then, computer malware spread via phone dial‐up bulletin boards and hand‐to‐hand as people copied each other’s software (both legally and illegally). Malware is still one of the most popular hacking methods.

NOTE

The first piece of malware I ever got “hit” by was an ansi bomb. A victim had to have a driver called ansi.sys loaded on their computer (via the config.sys) file, but this was a popular setup in the early days of IBM‐PC compatibles and the Disk Operating System (DOS).

Malware Types

The traditional types of malware are virus, worm, and Trojan horse. A computer virus is a self‐replicating program that when executed goes around looking for other programs (or sometimes, as with macro viruses, data) to infect. A computer worm is a replicating program that doesn’t usually modify other programs or data. It simply travels around on devices and networks using its own coded instructions, often exploiting one or more software vulnerabilities. A Trojan horse program masquerades as ...