San Francisco (May 17, 2018) – Purism, the social purpose corporation which designs and produces security focused hardware and software, has announced today that they are partnering with Nitrokey, maker of Free Software and Open Hardware USB OpenPGP security tokens and Hardware Security Modules (HSMs) to create Purekey, Purism’s own OpenPGP security token designed to integrate with its hardware and software. Purekey embodies Purism’s mission to make security and cryptography accessible where its customers hold the keys to their own security and follows on the heels of their announcement of a partnership with cryptography pioneer and GnuPG maintainer Werner Koch.
Purism customers will be able to purchase a Purekey by itself or as an add-on with a laptop order. For add-on orders, Purism can pre-configure the Purekey at the factory to act as an easy-to-use disk decryption key and ship laptops that are pre-encrypted. Customers will be able to insert their Purekey at boot and decrypt their drive automatically without having to type in a long passphrase. Customers will also be able to replace the factory-generated keys with their own at any time.
Purekey will also be a critical component in Purism’s tamper-evident boot protection. Purism will tightly integrate Purekey into their tamper-evident boot software so that customers will be able to detect tampering on their hardware from the moment it leaves the factory.
Enterprise customers have long used security tokens for easy and secure key management from everything from email encryption to code signing and multi-factor authentication. With Purekey, IT departments will have an integrated solution out of the box for disk and email encryption, authentication, and tamper-evident boot security that’s easy to use.
“Often security comes at the expense of convenience but Purekey provides a rare exception. By keeping your encryption keys on a Purekey instead of on a hard drive, your keys never leave the tamper-proof hardware. This not only makes your keys more secure from attackers, it makes using your keys on multiple devices more convenient. When your system needs to encrypt, decrypt, or sign something, just insert your Purekey; when you are done, remove it and put it back in your pocket.” — Purism CSO Kyle Rankin
“We’re pleased to be working with the Purism team, who are very aligned with our commitment to open hardware and free software. The possibilities of this partnership are exciting, especially given the growing importance of secure key storage on hardware smart cards and Purism’s important work on tamper-evident protection.” — Nitrokey CEO Jan Suhr
“We are long-time fans of Nitrokey as they are the only smart card vendor that shares our commitment to open hardware and free software. Their company and security products are a perfect complement to Purism’s belief that ethical computing means privacy and security without sacrificing personal control over your devices.” — Purism CEO Todd Weaver
About Nitrokey UG
Founded as an open source project in 2008 and turned into a full corporate entity in 2015, Nitrokey develops and produces highly secure open-source hardware and software USB keys that provide cryptographic functions for protecting; emails, files, hard drives, server certificates, online accounts and data at rest, preventing against identity theft and data loss.
About Purism
Purism is a Social Purpose Corporation devoted to bringing security, privacy, software freedom, and digital independence to everyone’s personal computing experience. With operations based in San Francisco (California) and around the world, Purism manufactures premium-quality laptops, tablets and phones, creating beautiful and powerful devices meant to protect users’ digital lives without requiring a compromise on ease of use. Purism designs and assembles its hardware in the United States, carefully selecting internationally sourced components to be privacy-respecting and fully Free-Software-compliant. Security and privacy-centric features come built-in with every product Purism makes, making security and privacy the simpler, logical choice for individuals and businesses.
We are excited about the future of Heads on Librem laptops and the extra level of protection it can give customers. As a result we’ve both been writing about it a lot publicly and working on it a lot privately. What I’ve realized when I’ve talked to people about Heads and given demos, is that many people have never seen a tamper-evident boot process before. All of the concepts around tamper-evident boot are pretty abstract and it can be difficult to fully grasp how it protects you if you’ve never seen it work.
We have created a short demo that walks through a normal Heads boot process and demonstrates tamper detection. In the interest of keeping the demo short I only briefly described what was happening. In this post I will elaborate on what you are seeing in the video.
Step One: Normal Boot
The normal boot process for a computer that uses Heads is much like with any other computer, at least from a user experience standpoint. Like with other computers, you can bring up a full menu of different items to boot, but you can also pick one to set as your default. Once you set a boot option as a default, at boot time you can just press Enter and it will boot into your operating system just like with any other system.
Default Heads Boot Menu
Unlike with other systems, Heads is providing extra levels of security during the boot process. At that default boot screen, you will see a 6-digit number above the menu options. That is a TOTP (Time-based One Time Password) code that Heads uses to prove to you that it hasn’t been tampered with and can be trusted. If you’ve ever used a TOTP code in the past, normally it’s so you can authenticate yourself to a website using Two-Factor Authentication. In this case it’s the reverse: the computer (specifically Heads) is authenticating itself to you! If that code matches the code on your phone, you know it’s safe to proceed.
Once you hit Enter during a normal boot, Heads then verifies the signatures of all of its configuration files stored in /boot based on the copy of your public GPG key it has within it. These configuration files include a file that contains sha256 checksums for the rest of the files in /boot. Once it verifies your signature for that file, Heads can trust it hasn’t been modified so it uses it to make sure the rest of the files in /boot haven’t changed. Since all of them match, they weren’t tampered with so Heads proceeds with the boot process.
Step Two: Hack The Computer
Hacking grub.cfg
Once the computer boots, I put my black hat on and “hack” my computer by defacing my /boot/grub/grub.cfg file with a comment. This is a benign hack for demonstration purposes, but the attacker could have just as easily modified grub.cfg to boot from an older kernel on your system that has a known security vulnerability, added a single user mode, or otherwise altered the boot process to make it easier to launch another attack.
An attack that changes a plain text configuration file leaves a trail that might be easier for a user to detect if they happened to edit the file themselves. A more sophisticated hacker would put a back door into your default initrd file (the initial file system your kernel uses when it boots) or even replace your kernel with a compromised version. Both of these kinds of attacks are almost impossible to detect without a system like Heads. Because all of these files are stored in /boot, and Heads checks all of them, it is able to detect all of these types of tampering.
Step Three: Detect Tampering
When the system reboots, it returns back to the main Heads boot screen. First I hit Enter to select the default boot option but this time when Heads scans all of the files in /boot, it detects that grub.cfg has been changed! Along with the warning, I also get the option to re-sign all of the files in /boot. This option exists because there are a number of perfectly legitimate reasons why your grub.cfg, initrd, kernel, or other /boot files might change either because you edited them yourself or you updated software that changed them. Otherwise if you don’t want to re-sign files you can return to the main menu.
Tampering detected!
If you choose to re-sign all of the files, you will get an additional warning screen that explains what Heads is about to do and another chance to exit out to the main menu. If you did choose to re-sign all of the files you would then insert a USB GPG smart card that held your private keys so you could re-sign the Heads configuration files in /boot.
Since I knew that I didn’t want to keep that “hacked” grub.cfg file, instead of signing the files I returned to the main menu. By default Heads used to error out to a recovery shell if it detected a file was tampered with. The assumption is that the expert user could then investigate and remedy the problem from within that shell. If you aren’t an expert user in this situation you might not know how to recover and would end up being locked out of your computer!
We understand that there are a number of situations where a user might legitimately or accidentally change files in /boot and while it’s not advisable to boot into a system that is actually tampered with by an attacker (because among other reasons, an attacker might be able to get your disk encryption or login passwords), we also don’t want to lock you out. We’ve added an “insecure boot mode” to Heads for these circumstances. When you select that option, Heads will ignore any tamper warnings and present you with a GRUB-style menu of boot options. You can then select a boot option and Heads will boot into your system. To make sure you know that this is an unsafe option, in addition to the warnings in the user interface, we also disable the splash screen and change the console to have a red background.
Insecure boot mode
Step Four: (Optionally) Investigate Tampering
So what should you do if Heads alerts you to tampering? Exactly how you respond to a potentially legitimate tampering alert depends on a number of factors including what kind of user you are. I’ll step through three of the most common categories of Heads user and describe how they might respond to a legitimate tampering alert.
Category 1: Enterprise User
In the event of tampering, enterprise users would just hand the laptop over to their IT team and pick up a replacement while the IT team investigates. Some organizations might want to go a step further and work with us to customize their Heads image with branded and customized warning messages with their custom policies or direct the employee to an internal wiki or other resources. Some enterprises may even want to go even further and remove the ability to boot a machine that sets off tampering alerts. This would also be useful for employees who take their machine overseas to ensure the machine is in a safe state before they reconnect it to the corporate network.
Once the IT team receives the laptop, they can then inspect the laptop for tampering using their in-house tools and procedures, and then reflash the system back to their secure, internal image. For smaller organizations who may not have those capabilities, Purism also provides support services to bring the laptop back to a clean factory state.
Category 2: Expert-level End User
The expert level user will likely want to inspect the system themselves in the event of a legitimate tamper alert. While I demonstrate the insecure forced boot mode in the demo, the expert user would likely use the Heads recovery shell or boot into a USB recovery disk instead (like the PureOS live install disk) to investigate from there. Otherwise, when they boot their compromised system, they will be prompted for their disk decryption passphrase and login password and risk turning those secrets over to the attacker.
While the Heads recovery shell is limited to a small subset of Linux command-line tools, it has enough tools for the expert user to inspect files in /boot including a text editor to inspect grub.cfg and tools to mount the encrypted root file system from a trusted environment. Provided you trust Heads itself hasn’t been tampered with, you could inspect quite a bit just from this recovery shell alone.
If the Heads recovery shell didn’t provide enough tools, the expert user could also boot from a USB disk, mount the /boot partition and inspect the changed files. In the case of a modified grub.cfg they would just use a text editor for this. In the case of a modified initrd they would need to extract the file and inspect the extracted file system. From there they could also decide to mount the root file system and inspect it for rootkits as well. For users who may suspect Heads itself was tampered with, they would be able to use flashrom to pull down a copy of the version of Heads on the system and inspect it directly.
Category 3: Everyone Else
The average user is unlikely to put on their forensics hat and inspect a compromised system. While for the most part any alerts an average user will see will likely be a direct result of package updates or other changes they know they made, there’s a possibility that sometimes they might get an alert they weren’t expecting. For instance, if you took your laptop overseas on a trip and didn’t update it or otherwise change it during the trip, a tampering alert when you got home would be much more suspicious.
So what’s the average user to do? No matter what, you can always fall back to the insecure boot mode so you won’t lose access to their system or files. In that case even if you couldn’t inspect or fix the errors yourself, you could at least backup your personal files and reinstall the OS to get back to a safe state. Alternatively like with enterprise users you could also take advantage of Purism support services to reflash your system to a factory state.
Conclusion
Hopefully watching Heads in action has helped make it a bit more clear just how it will protect you from tampering. In future posts I will walk through other Heads features and workflows including registering a new TOTP code and completely resetting the TPM.
Heads is cutting edge software and provides a level of security beyond what you would find in a regular computer. Up to this point though, its main user base are expert-level users who are willing to hardware flash their BIOS. The current user interface is also geared more toward those expert users with command-line scripts that make the assumption that you know a fair amount about how Heads works under the hood.
We want all our customers to benefit from the extra security in Heads so we intend to include it by default in all of our laptops in the future. For that to work though, Heads needs to be accessible for people of all experience levels. Most users don’t want to drop to a recovery shell with an odd error message so they can type some commands if they happen to update their BIOS, and they don’t want to be locked out of their system if they forgot to update their file signatures in /boot after a kernel update.
When we announced that we were partnering with Trammell Hudson to use Heads on our laptops, we didn’t just mean “thanks for the Free Software, see you later!” Instead, we are putting our own internal engineering efforts to the task of not just porting Heads to our hardware, but also improving it–and sharing those improvements upstream.
The Delicious GUI Center
The first of our improvements is focused on making the boot screen more accessible. We started by added whiptail (software that lets you display GUI menus in a console) to Heads so that we can display a boot menu that more closely resembles GRUB. We then duplicated the features of the existing Heads boot menu so that instead of this:
Heads booting on a Librem 13v2
you now see this:
Initial Heads GUI Menu
If you hit enter, you boot straight into your OS just like with GRUB, only behind the scenes Heads is checking all the files in /boot for tampering. If you hadn’t already configured a default boot option, instead of dumping you back to a main menu with no explanation or existing out to a shell, we decided to provide a GUI so you can decide what to do next:
No Default Boot Set
If you decide to load a menu of boot options from the main menu or from this dialog, we also wrapped a GUI around the Heads boot menu that parses your GRUB config file:
Heads Boot Selection Menu
In each of the most common workflows, we’ve replaced the console output with an easier-to-use menu that also provides a bit more explanation on what’s happening if something goes wrong. For the most part the average user will just verify the TOTP code and then hit Enter to boot their system so in that way it’s not much different from a standard GRUB boot screen. These extra menus come in only if the user ever needs to deviate from the default and select a different kernel, generate a new TOTP code, or do other maintenance within Heads.
What’s Next
We now have these GUI menus working well in our internal Heads prototypes and we’ve also pushed our changes upstream, where most of them have already been pulled into the Heads project. That said, having a GUI boot menu is only part of what you need to make tamper-evident boot usable. Now that the boot menu is in a good place, our next focus is on making the overall Heads bootstrap and update process, key management, and signature generation easy (if only we had a GPG expert to help us with smart card integration, that would sure make things easier). Keep an eye out for more updates along all these lines soon.
Protecting customer privacy, security and freedom is so fundamental to Purism’s mission that we codified it in our Social Purpose Corporation charter. We believe that these three concepts of privacy, security, and freedom are not just important by themselves but are also dependent on each other. For example, it’s obvious that by improving your security, we help protect your privacy. What might be less obvious is how dependent your privacy is on your freedom. True privacy means your computer and data are under your control, not controlled by unethical big-tech corporations. When your digital life is under your control you have the freedom to share your data only when you want to. So as we consider ways to improve your security, it can’t be at the cost of privacy or freedom.
As part of our goal to improve security we are excited to announce that we have successfully integrated Heads into our TPM-enabled coreboot-running Librem laptops. This integration effort began in April 2017 with the partnership of Purism and Trammell Hudson’s Heads project, which required hardware design changes, coreboot modifications, and operating system updates to reach where we are with this announcement today. We now have a tamper-evident boot process starting with the BIOS all the way through verifying that the kernel, initrd, and boot configuration files haven’t been changed in any way. Soon Heads will be enabled by default on all our laptops and this critical piece combined with the rest of our security features will make Librem laptops the most secure laptop you can buy where you hold the keys.
In this post we will describe why Heads is such an integral part of our security and how it combines with the rest of our features to create a unique combination of security, privacy and freedom that don’t exist in any other laptop you can buy today.
Heads booting on a Librem 13 with TPM
Why Tamper-Evident Software Matters
For your computer to be secure, you need to be able to trust that your software hasn’t been modified to run malicious code instead. This is one of many reasons why it’s so important that you can see the source code for all of the software on your system from your web browser to your hardware drivers to the kernel and up to your BIOS. We’ve gone to great lengths to choose hardware that can run with free software drivers, load our laptops with the FSF-endorsedPureOS, use coreboot as our Free/Libre and Open Source BIOS, and have neutralized and disabled the Intel Management Engine.
Unfortunately being able to see the source code isn’t enough. All of the software you run trusts the kernel, and the kernel trusts the BIOS. Without tamper-evident features that start the moment the computer turns on, an attacker can inject malicious code into your BIOS or kernel with no way to detect it. Once started, that malicious software could capture your encrypted disk or login passwords along with any other secrets or other personal information on your computer. By running tamper-evident software at boot, you get peace of mind that your system can be trusted before you start using it. With Purism’s combined approach the first bit loaded into the CPU is measured and signed by the user to prove nothing has been tampered with.
Heads Above the Rest
There are a number of different technologies we could have chosen to protect the boot process, but unfortunately very few of them are Free/Libre and Open Source and almost all of them work by taking control away from you and putting it into a vendor that owns the keys that determine what software you can run at boot. We have witnessed first-hand unethical laptops that ship with “Secure Boot” enabled (a technology that only allows software signed with pre-approved (e.g. paid-for) corporate controlled keys to run at boot). The very limited BIOS on this machine offered no way to disable Secure Boot so it is impossible to install Debian, PureOS or any other distribution that hadn’t gotten the BIOS vendor and Microsoft’s (paid) approval.
Heads has a lot of advantages over all of the other boot verification technologies that make it perfect for Librem laptops. First, it is Free Software that works with the Open Source coreboot BIOS so you don’t have to take our word for it that it is backdoor-free–anybody is free to inspect the code and build and install it (and customize it) themselves.
Second, the way it uses the TPM on your system to provide tamper-evidence puts the keys under your control, not ours. The fact that you retain control over the keys that secure your system is incredibly important. While we intend to make the secure boot process painless, we also don’t think you should have to trust us for it to work–you can change your keys any time.
Enterprise Level Security, Easily
If you manage a fleet of machines, this means with Purism Librem laptops that include TPM and Heads, you now have the ideal platform that you can tailor for your specific enterprise needs with custom features and your own trusted company keys. You can provide a trusted boot environment that protects your users from persistent malware and detects tampering while they travel, while still integrating with your custom in-house laptop images. And you can do this without having to ask us to sign your software.
The IT Security department’s dream of self-signed, tamper-evident, persistent-malware-detecting, laptop computer is now a reality with Purism Librem laptops.
Part of a Bigger Story
Having a secure boot process is the foundation of security on a modern laptop but it’s only part of the reason why Librem laptops are so secure. Here we will review some of the other security features that when combined with Heads puts Librem laptops in a totally different league.
Snitches get Switches
One of the first security features that set us apart was our hardware kill switches. Unlike a software switch that asks the hardware to turn off politely and hopes it listens, our hardware kill switches sever the circuit at the hardware level. This means you don’t have to worry about Remote Access Trojan malware that can disable your webcam LED to spy on you more easily. When you hit the radio kill switch, your WiFi is completely off, and when you hit the webcam/mic kill switch, the webcam is truly powered off–no webcam stickers needed.
Extra Security with Qubes
Our laptops default to PureOS because we feel it provides the best overall desktop experience for every type of user while still protecting your privacy, security and freedom. For customers who want an even higher level of security, Qubes uses virtualization features to provide extra security through compartmentalization. In 2015, our Librem 13 (version 1) was the first (and currently only) hardware to have received Qubes certification. Our current line of laptops remains compatible, and we recently announced that our current generation of Librem 13 and 15 laptops now fully work with Qubes 4.0.
We are also investigating ways to incorporate some of the compartmentalization features of Qubes into PureOS so you can still have good security but with an easier learning curve. Disposable web browsers and protected USB ports are just some of the features we are considering.
We Won’t Stop There
When you combine tamper-evident secure booting with Heads, an Open Source coreboot BIOS, a neutered and disabled Intel Management Engine, hardware kill switches, and the advanced security features of Qubes, Librem laptops have a security advantage over any other laptop you can buy. Equally important, they have extra security without sacrificing your privacy, freedom, or control. While we are excited to hit this major milestone, and can’t wait to have Heads on by default for all our laptops, we aren’t stopping there.
A secured boot process opens the possibility for even stronger tamper-evidence that extends further into the file system. From there you can move past tamper-evidence into tamper-resistance or even tamper-proofing in some advanced applications. We are also investigating better ways to incorporate hardware tokens with our products to provide more convenient authentication and encryption while still leaving the keys in your hands.
Ultimately, our goal is to provide you with the most secure computer you can buy that protects your privacy while also respecting your freedom. Since these values are inter-dependent, each milestone that improves one ultimately strengthens them all, and we will continue to work to raise the bar on all of them.
It’s easy to take things for granted when your computer runs a non-free proprietary BIOS. While the BIOS that comes with your computer is usually configured to match its features that’s not always the case. You end up with a sort of binary arrangement: if your BIOS supports a feature or allows you to change a setting, great, but if it doesn’t, you are generally out of luck. One example is with some of the new UEFI computers that ship with stripped-down BIOS options. One example we ran across recently had legacy boot disabled, secure boot enabled, and no way to change either setting, which is a terrible restriction for users wanting a free software distribution like PureOS or any another distribution that avoids the misnamed “secure boot” UEFI option.
From the beginning our goal has been to ship ethical computers without any proprietary code and the BIOS was one of our first targets. Starting last summer, all our computers come with the Free/Libre and Open Source coreboot BIOS. In addition to the many ethical and security advantages behind shipping an ethical BIOS/firmware, another advantage we have is that if our coreboot image doesn’t support a feature today, that doesn’t mean it won’t tomorrow.
We are happy to announce that due to the hard work of Youness “KaKaRoTo” Alaoui and Matt “Mr. Chromebox” DeVillier we have added IOMMU and TPM support to our new coreboot 4.7 BIOS. I’ve tested this personally on a Librem 13v2 with the latest Qubes 4.0-rc4 installer and the install completes with no warnings and reboots into a functional Qubes 4 desktop with working sys-net and sys-usb HVM VMs. In this blog post I’ll go over these different features, what they are, and why they are important. Read more
Spyware has long been a privacy and security risk for personal computers and has been used by a number of groups—ranging from creeps who spy on and blackmail people through Remote Access Trojans, to marketers who want ever more data about you for targeted ads (such as through the Superfish malware we’ve seen preinstalled on some “big brands” computers), to government intelligence agencies.
The Registerrecently reported on an investigation by the EFF and Lookout into the “Dark Caracal” spyware network. According to the EFF, this spyware has already captured hundreds of gigabytes of data. More troubling, this spyware network is being rented out to nation states that may not be able to develop this capability in-house. Who knew government spies had their own international app store?
The Dark Caracal toolkit contains malware that targets Windows and Android platforms. In particular, Lookout discovered that Dark Caracal uses a particular piece of Android malware called Pallas that disguises itself as a legitimate Signal or WhatsApp app and tricks the unsuspecting user into installing it. Instead of relying on a rootkit, it just uses the fact that chat apps usually have access to a wide variety of permissions on your phone, so most people don’t question all the permissions the malware wants. Once installed, it uses those permissions to get audio, text messages, files, and other data via completely legitimate means and uses the network connection to send it back to the attacker.
Purism, Post-Its and Personal Privacy
Dark Caracal relies on Windows and Android malware, so you might wonder why I’m writing about it at Purism given not only is our Librem 5 phone not out yet, but PureOS is a completely different platform and isn’t vulnerable to this spyware toolkit. What makes spyware like this relevant is that we have focused on protecting customer privacy from the beginning (it’s even part of our corporate charter). Stories like this give us an opportunity to audit the privacy and security protections we put in our products to see how they’d fare if we had been a target.
By performing a tabletop thought exercise against spyware in the wild even if we aren’t vulnerable ourselves, we can rate the protections we have in place against a real-world attack and proactively harden things further based on any gaps we might find. It’s always easier if you start with security as a focus from the beginning instead of tacking it on at the end, so this exercise is not just useful for our existing Librem laptops but is particularly helpful as we develop the Librem 5.
Software Delivery
The first thing to examine is the software delivery mechanism. Malicious lookalike applications are a constant problem in mobile app stores, even more so if you add third party stores into the mix. One advantage GNU/Linux distributions have long had against other operating systems is that all of a particular distribution’s applications come from its own official repository and are signed by its developers. It’s much more difficult for a malicious application to end up in the official repository and pass the signature check, so when you use your distribution’s tool to install LibreOffice, you can be assured you are getting the real thing.
We get an additional advantage due to our dedication to Free Software. Like with other GNU/Linux distributions, all applications in PureOS come from a central PureOS repository and are signed with official PureOS keys. Unlike many GNU/Linux distributions, PureOS is a FSF-endorsed distribution so all of the software in PureOS must be Free Software. PureOS doesn’t include packages that download proprietary codecs, unsigned Flash plugins or any other binary-only code from elsewhere on the Internet. This means you can examine the source for every package in PureOS to check for malware or backdoors.
This is why it’s important to be extra careful when adding third-party repositories or installing software with curl | sh because you bypass trusted code signing and lose many of the protections built into a GNU/Linux distribution’s native packages. Fortunately, because PureOS is derived in part from Debian, it can take advantage of the vast number of packages available in Debian’s free repository, so you are much less likely to need to install software from a third party.
Hardware Privacy Protections
For most vendors you would focus only on software protections against spying because that’s your only option. Fortunately we can go one step further because we also build privacy protections into the hardware itself in the form of kill switches. Purism devices include hardware switches that allow you to cut power to radio hardware (WiFi) and to the webcam and microphone. Unlike a software hot key, these hardware switches disconnect power from the hardware so it can’t be bypassed by malicious software. Dark Caracal attacked both desktops and phones and so we should consider what effect our hardware privacy features would have on the spyware in both cases.
Desktop Protections
On a traditional laptop infected with Dark Caracal, the attacker would be able to stream video from the webcam. Depending on the sophistication of the spyware, it could possibly capture video with the LED light off, a phenomenon that has been demonstrated multiple times in recent years. Even if the victim added the high-tech spying countermeasure of covering the webcam with tape, the attacker could still capture audio off of the microphone and stream it along with the rest of the data over the WiFi connection.
On Librem laptops, the radio kill switch disables WiFi and the webcam/mic kill switch—you guessed it—disables the webcam and microphone together. We recommend users take advantage of the kill switches, in particular the webcam/mic switch, to disable the hardware when you aren’t using it. With the webcam/mic kill switch, even if spyware found its way on your machine, the attacker wouldn’t be able to capture any video or audio from the machine as long as the switch was off.
Customers especially concerned about their privacy or in a high-risk environment could take the additional precaution of using the radio kill switch to keep WiFi powered off and only turning it on briefly when they needed a network connection. In that case the attacker would have to wait until a network connection showed up and use that limited window to upload the data.
Phone Protections
Like with the Librem laptops, the Librem 5 phone will have kill switches, but as you’ll see, they impact a phone’s privacy even more dramatically than on a laptop. For example, the webcam/mic kill switch will protect you in much the same way as in a laptop, but unlike with a laptop, it gives you spyware protection you just wouldn’t have with a traditional phone because most phones just don’t have a good way to disable the microphone (in fact they rely on it being always on for voice commands). While you could tape over the camera like in a laptop, almost no one does. With a kill switch, you can leave your camera and mic off and conveniently turn it on when you need to take a selfie or make a call.
The radio kill switch would protect you in a similar way as on a laptop, but the Librem 5 also has an additional baseband kill switch. This switch powers off the cellular radio completely, not using software like in traditional airplane mode but using hardware so you know for sure it’s off. With the baseband off, you also prevent spyware from using your cellular beacon to track your location or your cellular network to send out your personal data and rack up a large cellphone bill.
Conclusion
It’s hard to add security and privacy protections after the fact—even harder if your company relies on customer data for its revenue. Because we value customer privacy, we continually work to increase privacy protections in our products not just in a reactive way based on a specific threat but in a proactive and general-purpose way that applies to all kinds of threats. Even though Purism products weren’t vulnerable to Dark Caracal, you can see how some of the additional protections we put in place would help keep you safer even if they were.
While this government-sponsored spyware was interesting because of its scope and because it was rented out to other governments, spyware like it is sadly not unique. Everyone from governments to tech companies to hackers to creepy stalkers all want a piece of your personal data and they all use different kinds of spyware to get it. Some of the greatest minds in our generation are focused on the problem of how to capture and store more and more of your data. At Purism we recognize that this data is your data, and we work every day to protect it.
A modern computer has many different avenues for attack—ranging from local user-level exploits to root and kernel exploits, all the way down to exploits that compromise the boot loader or even the BIOS—but for over ten years the Intel Management Engine—with its full persistent access to all computer hardware combined with its secretive code base—has offered the theoretical worst-case scenario for a persistent invisible attack. The recent exploit from the talented group of researchers at Positive Technologies moves that worst-case scenario from “theoretical” to reality. While the proof-of-concept exploit is currently limited to local access, it is only a matter of time before that same style of stack smash attack turns remote by taking advantage of systems with AMT (Advanced Management Technology) enabled.
At its core, Purism fights for ethical computing and believes that free software is the best way to protect a user’s freedom, security, and privacy. This belief has meant investing in removing software that fails to provide these protections (due to their proprietary/non-free nature). From the beginning, Purism has seen the ethical issues and potential for abuse in the ME, and fought against the inclusion of the ME in CPUs starting with petitioning Intel for an ME-less design in 2016, then reverse engineering parts of the ME in 2017, to collaborating and cooperating with the other groups cleaning the ME—resulting in Purism being the first manufacturer to disable the Intel ME in modern hardware.
The recent Intel Management Engine exploit has left many wondering how they can protect themselves, not just from this attack but also any future ones that exploit software sitting at such a fundamental level on their computer.
Purism offers one of the most advanced approaches by combining secure hardware, TPM, coreboot, Heads, and the FSF-compliant PureOS in its Librem laptops, helping protect against a wide variety of ME, BIOS, and boot-loader attacks beyond just wiping ME code from the computer. Below we will discuss how Librem laptops can help protect against the current ME exploit and describe some of the limitations of these countermeasures. Read more
At its core, Purism fights for ethical computing and believes that free software is the best way to protect a user’s freedom, security, and privacy. This belief has meant investing in removing software that fails to provide these protections (due to their proprietary/non-free nature). From the beginning, Purism has seen the ethical issues and potential for abuse in the ME, and fought against the inclusion of the ME in CPUs starting with