One of the scariest realities of the Meltdown and Spectre vulnerabilities is just how widespread they are. Virtually every modern computer is affected in some way. The real question is how exactly are you affected? Every system is at a different state of vulnerability depending on which software has and hasn’t been patched.
Since Meltdown and Spectre are both fairly new and things are moving quickly, it’s not all that easy to tell what you need to look out for or what’s been fixed on your system. There are a couple of tools available that can help. They’re not perfect, but they can help you figure out what you need to know.
One of the top Linux kernel developers provided a simple way of checking the status of your system in regards to the Meltdown and Spectre vulnerabilities. This one is the easiest, and is most concise, but it doesn’t work on every system. Some distributions decided not to include support for this report. Even still, it’s worth a shot to check.
grep . /sys/devices/system/cpu/vulnerabilities/*
You should see output similar to the image above. Chances are, you’ll see that at least one of the vulnerabilities remains unchecked on your system. This is especially true since Linux hasn’t made any progress in mitigating Spectre v1 yet.
If the above method didn’t work for you, or you want a more detailed report of your system, a developer has created a shell script that will check your system to see what exactly it is susceptible to and what has been done to mitigate Meltdown and Spectre.
In order to get the script, make sure you have Git installed on your system, and then clone the script’s repository into a directory that you don’t mind running it out of.
cd ~/Downloads git clone https://github.com/speed47/spectre-meltdown-checker.git
It’s not a large repository, so it should only take a few seconds to clone. When it’s done, enter the newly created directory and run the provided script.
cd spectre-meltdown-checker ./spectre-meltdown-checker.sh
You’ll see a bunch of junk spit out into the terminal. Don’t worry, its not too hard to follow. First, the script checks your hardware, and then it runs through the three vulnerabilities: Spectre v1, Spectre v2, and Meltdown. Each gets its own section. In between, the script tells you plainly whether you are vulnerable to each of the three.
Each section provides you with a breakdown of potential mitigation and whether or not they have been applied. Here’s where you need to exercise a bit of common sense. The determinations that it gives might seem like they’re in conflict. Do a bit of digging to see if the fixes that it says are applied actually do fully mitigate the problem or not.
What This Means
So, what’s the takeaway? Most Linux systems have been patched against Meltdown. If you haven’t updated yet for that, you should. Spectre v1 is still a big problem, and not a lot of progress has been made there as of yet. Spectre v2 will depend a lot on your distribution and what patches it’s chosen to apply. Regardless of what either tool says, nothing is perfect. Do your research and stay on the lookout for information coming straight from the kernel and distribution developers.