Tailored Cyber Security.

Linux Nasties

I tweeted an article about how Linux isn’t free of viruses. I’ll tweet another one that takes it a step farther shortly. But, more importantly lets get to business.

Windows is, despite what you see on TV, the most used Operating System (OS) in the world. Behind that is Mac OS and then comes Linux. Seems funny that the amount of infections on given OS’s take that same order. Maybe that’s why people think Mac and Linux are safe from viruses?

#!/bin/bash
 
while true; do
    if [ “$(ps aux | grep firefox | grep -v “grep” | awk ‘{print $1}’)” != ‘root’ ]
    then
        killall firefox
    fi
done

Stupid, sure. Simple, definitely. That is a “virus” that will continually search for firefox running by anyone other than root and then close it. Actually, in this example it closes all instances of firefox so if root has one open along with another user then both instances will close.

Here’s my point, I just wrote that up real quickly to prove how easy it is. Maybe instead of killing firefox I’d start a keylogger, output everything to a file, then start DNS exfiltration. What’s DNS exfiltration? We’ll talk about it sometime, pretty sweet stuff.

I don’t think I need to make any more references or tell any stories. The 10ish lines of code above tell the story. Linux isn’t safe either. 

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