I wasn't planning on coming into work today. Today is supposed to be an easy day for me, a nice little break. I had a vacation, I put a video out, I made some Academy courses, and then I opened up Twitter and I saw this article. And I figured I kind of had to talk about it. So in this video, we're talking about another catastrophe in the world of information security, where apparently secure boot is completely broken on 200 plus models from five big device makers. Devices most likely meaning motherboards. So we're going to break down what this means, how it affects you, how you can check if you're compromised, and what's going on. Now if you're new here, hi, my name is Ed. This is a channel where I make videos about software security, cyber security, and all this other cool stuff. If you like that or just want to hang out, hit that sub button. My video rate is going up a lot because I guess the world's on fire. So if you want to get notifications, hit

that Bell as well sweet there has been a bit of a trend in information security. I guess to talk about this uh with this thing called secure boot now what what is secure boot well the problem with Computing in general is that if someone gets access to your computer they want to stay there right they want to keep doing evil stuff on your CPU. They want to do is they want to have what's called persistance right they write some code that stays on your computer and allows them to live there for a long time. Now ideally what a malicious actor really wants to do is to get as low level that's the name of the channel by the way just want to put it up little gang um low level as possible right uh and so you can live in a couple places you can live in user land as a regular user mode application. You can live in the kernel by a kernel mode rootkit which is what a lot of antiviruses do right they live in a way that they have privileged access.

to all of your information. Uh, but then you can live lower than that at a lower level. You can live in the motherboard at the UEFI level, right? You could hack the firmware on the motherboard to inject code into the OS. On the way up, you can do a lot of crazy stuff. Now, the issue, or I guess the good thing if you're, if you're not a hacker, if you are a person who wants to be secure, is there's a spec called Secure Boot. And what Secure Boot is, isn't even a link to Secure Boot. This just a UEFI spec. So there's a thing called Secure Boot. And what Secure Boot is supposed to be is you have a secret key that lives inside of your original equipment manufacturer that is used to verify the signature of your code. So, for example, when your board turns on, when your motherboard turns on, there is a crypto routine that checks that the signature so that the contents of the bootloader matches the signature that it's supposed to be, right, and that it's signed by a root trust Authority.

Certificate Authority. Right? And then from there, every stage in the chain as it boots up into the process validates the next stage. So for example, crypto routine will validate the UFI firmware. UFI firmware will use a derived key to check the OS, and the OS will check itself and go on from there. And then from there, you can do things like kernel module will sign verifications and all that other crazy stuff. And so the root of trust in all of these things are these things called keys, right? There is a series of keys: the platform key, the KEK, the KEKW, the key enrollment key, or the key exchange key, and the signature database that basically says these are the groups of things that we can trust right now. The issue is, so just like anything in the real world, it all comes down to a particular area that we all just decide to trust, right? The root of trust, the thing that cannot additionally be independently independently verified, we have to just put our trust in it. And so the independent piece of trust is the

root of Trust on the motherboard, which is again a super duper secret key that is owned by the original equipment manufacturer. But the public key lives in that crypto device, and they use that public key to verify the signature that is done with the private Key. Well, what if I told you that the private key that runs uh about 200 device models from Acer, Dell, gigabyte, Intel, and super micro uh was posted on GitHub in 2022, and you can watch this guy down there also reacting to it. He's not super happy either. This ad's a little weird anyway um yeah so that's kind of cool, but it turns out well hold on guys that platform key, which again is the root of trust of our motherboards, uh was stored in an encrypted form ah it's encrypted. They used the passphrase good old good old ryzen I guess or whoever decided delete this password um yeah so that's fine turns out binarily the the security research team that found this issue turns out this encrypted file uh was protected by a four-character password.

so even if they were using like military-grade encryption like AES256, if you know it's four characters, that's like semi-trivial to break. So they did, um, and now they just have the private key from this OEM manufacturer that, again, is used apparently in, uh, they tested 25 devices that they were able to acquire and get the signature for. And so you may be asking, like, okay, exactly what could happen if somebody is able to own secure Boots. The threat posed by PK fail, which is the name of like this class of vulnerability, is that anyone with knowledge of the private portion of the affected platform key, so again the part that was encrypted on GitHub but now has been decrypted, and admin rights of an affected device can completely bypass secure boot protections. The threat is most immediate for devices that use a platform key compromised in the 2022 leak on GitHub. The problem with the leaked private portion of the platform key is anyone who owns the private key owns secure boot on that specific device, literally because by having the private

key. You can issue certificates that are signed by the OEM. And when you do the public key validation of those signed certificates, you know, like they're valid. You just, you've made a real certificate, right? They can not only modify revocations to the revoked binary, but can also create their own key exchange key or the KEK. And then also add their own certificates into the DB database. And I'll go to a chart down here later to show you kind of the graph of all these things. And the DB database specifies everything that can be executed during the boot. So they can make a binary compatible with UEFI Secure Boot on these machines where the attacker controls the platform key. And I've talked about this in previous videos. There's literally a UEFI boot kit you can buy online. I think it's actually open source now, but it was for sale in some black market for like five grand, um, which is cheap by the way. The world's first known instance of a world UEFI dwelling malware that bypassed secure.

boot now because they took advantage of a different secure boot vulnerability. It no longer worked, but this discovery says that, you know, it would not only make Black Lotus work again, but it would be able to create other malware and enable it on all these devices. And again, it's over 250 of these OEM manufacturers that build motherboards that install signed UFI firmware onto these motherboards. So absolutely wild. Now, if you do get hacked by one of these attacks, and you do get your system taken over, there is a chance that hackers could take control of your data. The way they do this is they watch you type in keystrokes, and they make sure that they know the way to get into your accounts. They might be able to take over your bank accounts and do all sorts of nefarious stuff. So to mitigate this, I like to use two-factor authentication. And this platform that I depend on the most is the UB Key by UBO. Now, the reason I like this so much is, since one, the UB Key is super lightweight. I literally

have a lanyard that I carry around with. I can just plug it into the computer, and it works on a ton of different platforms. I can actually store my SSH keys for my server on the UB key itself, and I can use that to securely get into my servers for all my websites. There are tons of platforms that you can make yourself more secure right now. You can use my link in the description below to get $5 off your UB key that's compatible with all these platforms and more. Protect yourself online and use two-factor authentication by UBO with the UB key. UBO, thank you for sponsoring today's video. Back to the video. So to kind of give an example of how, like, cryptographically, this all breaks down, if you don't know a ton about, like, public key infrastructure or how digital signing works effectively, all you need to know is that the platform key, the PK, is an asymmetric key system that has a private key and a public key. Ideally, the origin or the holder of the private key doesn't want

anyone else to know it it's private. It is able to distribute the public key, which is the decryption key that allows you to verify the signature, right? So you encrypt a thing that is a signature. You do a decryption to verify that the hash matches. You have verified the signature. Okay, awesome. Now, if for example, the owner of the platform key wanted to give a derivative key to a device manufacturer or someone that uses a system on their motherboard or like the Windows operating system, for example, they create a key exchange key, which can be provably associated to the platform key as a, you know, chain of trust, but can also do further key derivations. And what it does is it does signatures inside of this signature database and disallowed signature database, which is kind of like a revocation and allowance list, kind of like a signature revocation list but for binary I not certificates, right? And these all ship in these different forms. And so you'll notice here is that the thing that got leaked on GitHub that was encrypted with a 4-byte password is the

platform key. So, if any of the devices depend on a chain of trust where that platform key is involved, the entire chain is compromised. So, they could effectively inject themselves into this process at any stage. At the root, they own the entire process. So, right now, you can run one of these two commands. You can run this command in Windows PowerShell if you're a freak and use PowerShell, or this command if you run Linux. And see is the root of trust platform key for your device. First of all, it literally says do not trust, do not ship in the certificate name. So, like, that's kind of hilarious. But also, it has a unique serial number, which is like how keys work, right? They have serials. If it has this certificate serial number, or it has literally like do not ship me, please in the CT, then you're compromised. And that means that someone who gets access to your system could have a complete secure boot bypass and possibly go as low level with persistence as the bootloader of your

CPU itself right. So, not a great place to be, I think. This whole situation begs a really interesting question about trust, you know. We have these things on our computers that are called roots of trust. You have to inherently just trust that they're secure and overall they do a good job. I mean, I want to make sure that we all take away from this that secure boot is a good thing. The idea behind cryptographically verifying the entire chain of software up to your OS is a good thing. But the problem with these systems that are cryptographic in nature is that they're so complicated and so easy to mess up. The minute one part of them goes wrong, the entire chain kind of crumbles. And you can see that this is such an issue because in a supply chain scenario, we have had 200 plus models from five different manufacturers get compromised from this one slip up where they even encrypted it just not enough. Anyway, guys, that's it for now. Thanks for watching. I really appreciate it. Go grab a UB key, buy UB Cod, protect yourself.

online and then go check out this video. Video? Nope, this video where I think you learn about something just as interesting. We'll see you there.

this is getting ridiculous...

Teaching you 🧠 about the lowest level
