[0x47] What UNIX virus can do

Good day!

What is a virus?

A virus is a code or program that infects system files, program files, critical files, and processes on a system. They are used to spread throughout your computer system very quickly and persistence, sometimes might destroy your system.

First question that might come in your mind if you are a linux/UNIX user is:
Is it possible for my Linux/UNIX box to become infected with a virus or malware?

The short answer is YES, it is certainly possible to have viruses under UNIX or UNIX-like operating system like Linux, however in the wild, there are no widespread Linux viruses on it, unlike windows which is the grand plague of all the amazing viruses and unknown malware and have more population than of UNIX virii.

The virus is hard to detect, it can also turns your operating system into a flood network usually kiddies are tend to use these kind of methods like DoS or DDoS a certain web host or a game server. Other viruses on UNIX downloads from remote website directly from the infected box, and then loads a backdoor into every daemon in inetd (such files provide more obscure hiding places, and are often more "active").

Virus's are very fascinating, their existence is superior to that of the mind controlling human. A UNIX virus can do basically anything with the correct privileges. Once it have the correct permissions, it can infect many processes on the system. They can also differ from the other. This is what we call maximum stealthism, thus it makes it hard for virus detection program to detect it. Running many virus's is called a "parade" among virus writers.

So how it can infect Linux/UNIX systems? Usually an intruder gain access to a remote system and installed the virus as a backdoor to the systems which can listen to a certain port, using back connect or even on other service which you can issue command eg IRC server.

In conclusion, a unix virus can do anything to your system once infected.