Linux is something of an oddity. It's a free, highly secure operating system that runs everything from the computers that are the backbone of the Internet to enterprise computers to desktops to tiny gadgets like the $35 Raspberry Pi. Linux is also the foundation for the Android operating system.
Even with all that, very few people have heard of it. One of the reasons is that for a long time only hard-core techies could actually get it running on the average desktop or laptop. That's changed a lot, with many versions, such as Linux Mint, being just as easy to use as Windows. We've even recommended it in the past as a cheap, secure operating system for an older computer.
Security is one of Linux's great claims to fame. It has tens of thousands of developers around the world checking the code and writing their own free programs anyone can use or adapt. That's why there are almost no Linux viruses, and any major security flaws get spotted and fixed fairly quickly.
One of those flaws popped up recently, even though it wasn't exactly spotted as quickly as Linux users would hope. That could be because it was an incredibly basic problem.
The flaw was found in the Grub2 program that many versions of Linux use as a bootloader. This is the program that starts the operating system and lets you manage multiple operating systems on the same computer.
Security researchers found that when Grub2 is active, pressing the backspace key on the keyboard exactly 28 times launches the "Grub rescue shell." The rescue shell is a very basic operating system that lets a user repair problems when a main operating system is having serious trouble.
However, the rescue shell can also let an attacker bypass the computer's security to steal files or install their own malicious programs. Of course, the attacker also needs access to your computer and some serious tech know-how to actually use the Grub rescue shell if they bring it up.
The major Linux companies have already fixed the problem, so if you update Linux regularly you should be OK.