Another Bloomberg Story about Supply-Chain Hardware Attacks from China

Bloomberg has another story about hardware surveillance implants in equipment made in China. This implant is different from the one Bloomberg reported on last week. That story has been denied by pretty much everyone else, but Bloomberg is sticking by its story and its sources. (I linked to other commentary and analysis here.) Again, I have no idea what’s true….

Bloomberg has another story about hardware surveillance implants in equipment made in China. This implant is different from the one Bloomberg reported on last week. That story has been denied by pretty much everyone else, but Bloomberg is sticking by its story and its sources. (I linked to other commentary and analysis here.)

Again, I have no idea what's true. The story is plausible. The denials are about what you'd expect. My lone hesitation to believing this is not seeing a photo of the hardware implant. If these things were in servers all over the US, you'd think someone would have come up with a photograph by now.

EDITED TO ADD (10/12): Three more links worth reading.

from https://www.schneier.com/blog/

Chinese Supply Chain Hardware Attack

Bloomberg is reporting about a Chinese espionage operating involving inserting a tiny chip into computer products made in China. I’ve written about (alternate link) this threat more generally. Supply-chain security is an insurmountably hard problem. Our IT industry is inexorably international, and anyone involved in the process can subvert the security of the end product. No one wants to even…

Bloomberg is reporting about a Chinese espionage operating involving inserting a tiny chip into computer products made in China.

I've written about (alternate link) this threat more generally. Supply-chain security is an insurmountably hard problem. Our IT industry is inexorably international, and anyone involved in the process can subvert the security of the end product. No one wants to even think about a US-only anything; prices would multiply many times over.

We cannot trust anyone, yet we have no choice but to trust everyone. No one is ready for the costs that solving this would entail.

EDITED TO ADD: Apple, Amazon, and others are denying that this attack is real. Stay tuned for more information.

EDITED TO ADD (9/6): TheGrugq comments. Bottom line is that we still don't know. I think that precisely exemplifies the greater problem.

EDITED TO ADD (10/7): Both the US Department of Homeland Security and the UK National Cyber Security Centre claim to believe the tech companies. Bloomberg is standing by its story. Nicholas Weaver writes that the story is plausible.

from https://www.schneier.com/blog/

Speculation Attack Against Intel’s SGX

Another speculative-execution attack against Intel’s SGX. At a high level, SGX is a new feature in modern Intel CPUs which allows computers to protect users’ data even if the entire system falls under the attacker’s control. While it was previously believed that SGX is resilient to speculative execution attacks (such as Meltdown and Spectre), Foreshadow demonstrates how speculative execution can…

Another speculative-execution attack against Intel's SGX.

At a high level, SGX is a new feature in modern Intel CPUs which allows computers to protect users' data even if the entire system falls under the attacker's control. While it was previously believed that SGX is resilient to speculative execution attacks (such as Meltdown and Spectre), Foreshadow demonstrates how speculative execution can be exploited for reading the contents of SGX-protected memory as well as extracting the machine's private attestation key. Making things worse, due to SGX's privacy features, an attestation report cannot be linked to the identity of its signer. Thus, it only takes a single compromised SGX machine to erode trust in the entire SGX ecosystem.

News article.

The details of the Foreshadow attack are a little more complicated than those of Meltdown. In Meltdown, the attempt to perform an illegal read of kernel memory triggers the page fault mechanism (by which the processor and operating system cooperate to determine which bit of physical memory a memory access corresponds to, or they crash the program if there's no such mapping). Attempts to read SGX data from outside an enclave receive special handling by the processor: reads always return a specific value (-1), and writes are ignored completely. The special handling is called "abort page semantics" and should be enough to prevent speculative reads from being able to learn anything.

However, the Foreshadow researchers found a way to bypass the abort page semantics. The data structures used to control the mapping of virtual-memory addresses to physical addresses include a flag to say whether a piece of memory is present (loaded into RAM somewhere) or not. If memory is marked as not being present at all, the processor stops performing any further permissions checks and immediately triggers the page fault mechanism: this means that the abort page mechanics aren't used. It turns out that applications can mark memory, including enclave memory, as not being present by removing all permissions (read, write, execute) from that memory.

EDITED TO ADD: Intel has responded:

L1 Terminal Fault is addressed by microcode updates released earlier this year, coupled with corresponding updates to operating system and hypervisor software that are available starting today. We've provided more information on our web site and continue to encourage everyone to keep their systems up-to-date, as it's one of the best ways to stay protected.

I think this is a comprehensive link to everything the company is saying about the vulnerability.

from https://www.schneier.com/blog/

Another Spectre-Like CPU Vulnerability

Google and Microsoft researchers have disclosed another Spectre-like CPU side-channel vulnerability, called "Speculative Store Bypass." Like the others, the fix will slow the CPU down. The German tech site Heise reports that more are coming. I’m not surprised. Writing about Spectre and Meltdown in January, I predicted that we’ll be seeing a lot more of these sorts of vulnerabilities. Spectre…

Google and Microsoft researchers have disclosed another Spectre-like CPU side-channel vulnerability, called "Speculative Store Bypass." Like the others, the fix will slow the CPU down.

The German tech site Heise reports that more are coming.

I'm not surprised. Writing about Spectre and Meltdown in January, I predicted that we'll be seeing a lot more of these sorts of vulnerabilities.

Spectre and Meltdown are pretty catastrophic vulnerabilities, but they only affect the confidentiality of data. Now that they -- and the research into the Intel ME vulnerability -- have shown researchers where to look, more is coming -- and what they'll find will be worse than either Spectre or Meltdown.

I still predict that we'll be seeing lots more of these in the coming months and years, as we learn more about this class of vulnerabilities.

from https://www.schneier.com/blog/

Another Branch Prediction Attack

When Spectre and Meltdown were first announced earlier this year, pretty much everyone predicted that there would be many more attacks targeting branch prediction in microprocessors. Here’s another one: In the new attack, an attacker primes the PHT and running branch instructions so that the PHT will always assume a particular branch is taken or not taken. The victim code…

When Spectre and Meltdown were first announced earlier this year, pretty much everyone predicted that there would be many more attacks targeting branch prediction in microprocessors. Here's another one:

In the new attack, an attacker primes the PHT and running branch instructions so that the PHT will always assume a particular branch is taken or not taken. The victim code then runs and makes a branch, which is potentially disturbing the PHT. The attacker then runs more branch instructions of its own to detect that disturbance to the PHT; the attacker knows that some branches should be predicted in a particular direction and tests to see if the victim's code has changed that prediction.

The researchers looked only at Intel processors, using the attacks to leak information protected using Intel's SGX (Software Guard Extensions), a feature found on certain chips to carve out small sections of encrypted code and data such that even the operating system (or virtualization software) cannot access it. They also described ways the attack could be used against address space layout randomization and to infer data in encryption and image libraries.

Research paper.

from https://www.schneier.com/blog/

Adding Backdoors at the Chip Level

Interesting research into undetectably adding backdoors into computer chips during manufacture: "Stealthy dopant-level hardware Trojans: extended version," also available here: Abstract: In recent years, hardware Trojans have drawn the attention of governments and industry as well as the scientific community. One of the main concerns is that integrated circuits, e.g., for military or critical-infrastructure applications, could be maliciously manipulated during…

Interesting research into undetectably adding backdoors into computer chips during manufacture: "Stealthy dopant-level hardware Trojans: extended version," also available here:

Abstract: In recent years, hardware Trojans have drawn the attention of governments and industry as well as the scientific community. One of the main concerns is that integrated circuits, e.g., for military or critical-infrastructure applications, could be maliciously manipulated during the manufacturing process, which often takes place abroad. However, since there have been no reported hardware Trojans in practice yet, little is known about how such a Trojan would look like and how difficult it would be in practice to implement one. In this paper we propose an extremely stealthy approach for implementing hardware Trojans below the gate level, and we evaluate their impact on the security of the target device. Instead of adding additional circuitry to the target design, we insert our hardware Trojans by changing the dopant polarity of existing transistors. Since the modified circuit appears legitimate on all wiring layers (including all metal and polysilicon), our family of Trojans is resistant to most detection techniques, including fine-grain optical inspection and checking against "golden chips". We demonstrate the effectiveness of our approach by inserting Trojans into two designs -- a digital post-processing derived from Intel's cryptographically secure RNG design used in the Ivy Bridge processors and a side-channel resistant SBox implementation­ -- and by exploring their detectability and their effects on security.

The moral is that this kind of technique is very difficult to detect.

from https://www.schneier.com/blog/

New Spectre/Meltdown Variants

Researchers have discovered new variants of Spectre and Meltdown. The software mitigations for Spectre and Meltdown seem to block these variants, although the eventual CPU fixes will have to be expanded to account for these new attacks….

Researchers have discovered new variants of Spectre and Meltdown. The software mitigations for Spectre and Meltdown seem to block these variants, although the eventual CPU fixes will have to be expanded to account for these new attacks.

from https://www.schneier.com/blog/

Spectre and Meltdown Attacks Against Microprocessors

The security of pretty much every computer on the planet has just gotten a lot worse, and the only real solution — which of course is not a solution — is to throw them all away and buy new ones. On Wednesday, researchers just announced a series of major security vulnerabilities in the microprocessors at the heart of the world’s…

The security of pretty much every computer on the planet has just gotten a lot worse, and the only real solution -- which of course is not a solution -- is to throw them all away and buy new ones.

On Wednesday, researchers just announced a series of major security vulnerabilities in the microprocessors at the heart of the world's computers for the past 15-20 years. They've been named Spectre and Meltdown, and they have to do with manipulating different ways processors optimize performance by rearranging the order of instructions or performing different instructions in parallel. An attacker who controls one process on a system can use the vulnerabilities to steal secrets elsewhere on the computer. (The research papers are here and here.)

This means that a malicious app on your phone could steal data from your other apps. Or a malicious program on your computer -- maybe one running in a browser window from that sketchy site you're visiting, or as a result of a phishing attack -- can steal data elsewhere on your machine. Cloud services, which often share machines amongst several customers, are especially vulnerable. This affects corporate applications running on cloud infrastructure, and end-user cloud applications like Google Drive. Someone can run a process in the cloud and steal data from every other users on the same hardware.

Information about these flaws has been secretly circulating amongst the major IT companies for months as they researched the ramifications and coordinated updates. The details were supposed to be released next week, but the story broke early and everyone is scrambling. By now all the major cloud vendors have patched their systems against the vulnerabilities that can be patched against.

"Throw it away and buy a new one" is ridiculous security advice, but it's what US-CERT recommends. It is also unworkable. The problem is that there isn't anything to buy that isn't vulnerable. Pretty much every major processor made in the past 20 years is vulnerable to some flavor of these vulnerabilities. Patching against Meltdown can degrade performance by almost a third. And there's no patch for Spectre; the microprocessors have to be redesigned to prevent the attack, and that will take years. (Here's a running list of who's patched what.)

This is bad, but expect it more and more. Several trends are converging in a way that makes our current system of patching security vulnerabilities harder to implement.

The first is that these vulnerabilities affect embedded computers in consumer devices. Unlike our computer and phones, these systems are designed and produced at a lower profit margin with less engineering expertise. There aren't security teams on call to write patches, and there often aren't mechanisms to push patches onto the devices. We're already seeing this with home routers, digital video recorders, and webcams. The vulnerability that allowed them to be taken over by the Mirai botnet last August simply can't be fixed.

The second is that some of the patches require updating the computer's firmware. This is much harder to walk consumers through, and is more likely to permanently brick the device if something goes wrong. It also requires more coordination. In November, Intel released a firmware update to fix a vulnerability in its Management Engine (ME): another flaw in its microprocessors. But it couldn't get that update directly to users; it had to work with the individual hardware companies, and some of them just weren't capable of getting the update to their customers.

We're already seeing this. Some patches require users to disable the computer's password, which means organizations can't automate the patch. Some antivirus software blocks the patch, or -- worse -- crashes the computer. This results in a three-step process: patch your antivirus software, patch your operating system, and then patch the computer's firmware.

The final reason is the nature of these vulnerabilities themselves. These aren't normal software vulnerabilities, where a patch fixes the problem and everyone can move on. These vulnerabilities are in the fundamentals of how the microprocessor operates.

It shouldn't be surprising that microprocessor designers have been building insecure hardware for 20 years. What's surprising is that it took 20 years to discover it. In their rush to make computers faster, they weren't thinking about security. They didn't have the expertise to find these vulnerabilities. And those who did were too busy finding normal software vulnerabilities to examine microprocessors. Security researchers are starting to look more closely at these systems, so expect to hear about more vulnerabilities along these lines.

Spectre and Meltdown are pretty catastrophic vulnerabilities, but they only affect the confidentiality of data. Now that they -- and the research into the Intel ME vulnerability -- have shown researchers where to look, more is coming -- and what they'll find will be worse than either Spectre or Meltdown. There will be vulnerabilities that will allow attackers to manipulate or delete data across processes, potentially fatal in the computers controlling our cars or implanted medical devices. These will be similarly impossible to fix, and the only strategy will be to throw our devices away and buy new ones.

This isn't to say you should immediately turn your computers and phones off and not use them for a few years. For the average user, this is just another attack method amongst many. All the major vendors are working on patches and workarounds for the attacks they can mitigate. All the normal security advice still applies: watch for phishing attacks, don't click on strange e-mail attachments, don't visit sketchy websites that might run malware on your browser, patch your systems regularly, and generally be careful on the Internet.

You probably won't notice that performance hit once Meltdown is patched, except maybe in backup programs and networking applications. Embedded systems that do only one task, like your programmable thermostat or the computer in your refrigerator, are unaffected. Small microprocessors that don't do all of the vulnerable fancy performance tricks are unaffected. Browsers will figure out how to mitigate this in software. Overall, the security of the average Internet-of-Things device is so bad that this attack is in the noise compared to the previously known risks.

It's a much bigger problem for cloud vendors; the performance hit will be expensive, but I expect that they'll figure out some clever way of detecting and blocking the attacks. All in all, as bad as Spectre and Meltdown are, I think we got lucky.

But more are coming, and they'll be worse. 2018 will be the year of microprocessor vulnerabilities, and it's going to be a wild ride.


Note: A shorter version of this essay previously appeared on CNN.com. My previous blog post on this topic contains additional links.

from https://www.schneier.com/blog/