Intel Management Engine cleaner
github.com
github.com
Don't get me wrong, I love some of the benefits like remote control of my servers, fan speed control, monitoring of temps and voltages etc. but I do think we've given up a LOT of security for the sake of convenience. It wouldn't take much for a well crafted worm or heck a simple script to disrupt a whole network of ME/AMT enabled clients and servers.
AMT on the other hand provides its network functionality by hijacking the host's IP, and siphoning off traffic destined for its ports (16992 and 16993). This is one of the things that makes it scary, and just one of the differences between it and IPMI.
Source: I have worked extensively with AMT and built a semi-open-source Python management library for it in a previous job.
https://www.thomas-krenn.com/en/wiki/Nuvoton_WPCM450R_IPMI_C...
Oracle uses these:
If your PC doesn't use an Intel ethernet/wifi chip you're 100% safe from remote execution attacks because AMT only works with Intel chips.
Worse: There is no reason you couldn't have both. For a start: A simple "off" switch for Intel ME would please a lot of people.
But not a corporate security team, of course. It's not that simple.
Businesses can simply tell their employees to leave it enabled or find another job.
A corporate security team wants to make sure that whether ME is on or off, it stays that way and can't be flipped by someone with temporary access or by malware. That's exactly what individual end users want too for their computing freedom.
Users often aren't the owners of their computer. Currently that means the computer may act against the interest of its user. I'd rather have a world where users can trust their computers even at the expense of the owners' control.
While a physical ME switch is vulnerable to physical attacks, it does seem like the best approach we have today for minimizing owners' ability to subvert the user.
You can satisfy "do not betray the user" and "do not betray the owner" if you have a locked-down computer like a Chromebook that only accepts signed firmware and signed OSes. That way, no user of the computer, owner or otherwise, can make permanent changes to it that will compromise other users; guests are protected from the owner just as much as the owner is protected from guests.
You can satisfy "do not betray the user" and "have full freedom" if you have a computer with no protections against OS modification (the traditional PC architecture), but that is susceptible to physical attacks, where a user can subvert the owner. And every user needs to subvert the machine afresh in order for the computer not to betray them to the previous user; this is a risky model for things like shared computer labs.
You can satisfy "do not betray the owner" and "have full freedom" with an architecture where the owner gets a password/key that unlocks management functions or BIOS reconfiguration, and physical access (short of desoldering) is insufficient to access those functions.
I'm a fan of that latter model. Of course, I do have the resources to own a computer of my own for my personal computing, which biases my preferences. There's a good argument for building a more just world for people whose only computers are shared computers (libraries, work-issued laptops, etc.), but I think smartphones are becoming ubiquitous enough that we can expect that everyone will soon have a device they own for their own computing.
One possibility I like to think about for PCs is replacing usernames with a root of trust (hash). A trusted ROMed hypervisor downloads the configuration (or loads from cache) and netboots.
But ultimately it's bigger than PCs. Embedded computing is becoming pervasive and allows easier monitoring and control of what people can and cannot do. Today people accept that owners or manufacturers can set whatever policy they like even if it's user-hostile.
The problem with this model is that it destroys freedom as soon as the user isn't the owner. That is somewhat what corporate IT departments are looking for, but it's even more problematic when a person goes to the store and brings home a device that some corporation has already appointed itself "owner" of. In other words, the third model devolves into the first.
And it doesn't really buy you anything. If you use FDE and erase the decryption key from memory when not using the computer then you don't need hardware to protect your data, math is already protecting it. Past that you can only want to prevent compromise of the boot loader, but in that case detection is just as good as prevention which makes prevention an unnecessary evil.
And lab environments don't need this either. There you put padlocks on the computers after setting the flash write protect jumper, don't even install hard drives in them and boot from the network. It's the same situation -- detection is more important than prevention. Someone can cut the lock but then you know that computer is compromised.
In that setup, even if someone stole your laptop, it would be unusable, short of opening it up and fully resetting the BIOS/UEFI to its factory state, correct?
(My laptop has full-disk LUKS, a BIOS/UEFI password and doesn't boot from USB, but I still have TPM disabled and haven't signed my Grub bootloader yet.)
this is a clear "think of the children" excuse.
The IME in contrast is pitched at corporate and government systems to allow sysadmins to better manage things. Effectively LOM for the corporate desktop.
There's been quite a bit of controversy over Intel ME, in discussions with those that know about it at least, so I don't think that's a fair assessment.
It should have been distributed as an optional, removable hardware dongle. There was no need to bake it into the hardware. Same for AMD PSP as well.
Control over this processor identification facility is supposed to be offered as a user-accessible control in UEFI, to "enable, leave disabled but unlocked, and lock disabled". Once "lock disabled", it cannot be enabled back again until a hard reset happens.
Also, unlike the Pentium III "processor serial number cpuid", you need to read a MSR to access the new version, so it is supposed to be restricted to the O.S. kernel, which could then either make it available to regular programs or not.
It is not easy to find out about it, either: it is hidden in plain sight on the public Intel SDM (the processor's manual). You need to look over all the model-specific MSRs with a magnifying glass until you find it :-)
In the end, it boils down to whether your favorite O.S. cares about your privacy or not. It can lock the thing disabled at early boot, denying access to everything other than UEFI.
20 years ago most people would have sued anyone revealing to the world what they and their kids are happily telling on Facebook today. Give them some more years and they will pray to have a SWAT team guarding their bedroom when they're sleeping.
One of my coworkers told me he previously worked on the motherboard team for Intel and was regaling the office with stories about testing the motherboards against the latest games. Apparently many of the Intel engineers personally tested overclocking the processors to see how much they could take before they fried.
At some point I asked him if he knew anything about the Management Engine. He said that they were starting to become a thing right around the time he was leaving, so he didn't know too much about them. I said, "Well, there's a bunch of paranoid people that are uneasy about it because, to my understanding, it's a blackbox second processor and we really have no idea what it's doing."
Without prompt, he replied, "Oh, you mean like the FBI using it to listen in? Yeah, that happened. It happened on AT&T's when I went over there as well."*
That's my story. I apologize if it looks like I'm spreading FUD here, since I'm not going to give up my name or my coworker's to verify the story, but I sincerely doubt that Intel would acknowledge such a capability anyway, so, take it as you will. Libreboot, the Management Engine cleaner, and other such projects need to exist. My coworker's comment convinced me of that.
* I'm not sure what he's referring to here. Maybe someone else can shed some light. Does AT&T make processors?
And there have been versions of the Intel ME in the wild with known remote exploits AFAIK.
The world is a pretty ridiculous place, even with the best efforts of those ridiculous FSF zealots. I don't always agree with them and their methods and communication skills aren't perfect, and it's a shame to see coreboot/libreboot get fragmented etc... but imagine how backwards the world would be without some people taking things 'a bit too far sometimes'.
Anecdotally, I also found Libreboot easier to build. There is less configuration involved.
So, basically any computer?
Also, how safe is it?
EDIT:
> Bricking is very likely to happen! Just in case you didn't hear me the first time
There is microcode-level integration between the IME and the system processor in an Intel system. It also involves the platform TPM (which could be an IME module), on systems where Intel SGX or Intel TXT is active.
OTOH, if the non-critical IME modules are missing, the system boots and goes on working just fine. Since the IME "partition table" is not signed, this allows you to remove the undesired modules such as Intel AMT.
It is actually possible for a system integrator/motherboard factory to request from Intel a minimal IME build that lacks AMT, you know.
It is also rather trivial to disable the (documented) IME path to the network: don't use the chipset-embedded ethernet MAC (as in midia access controller, not MAC address). That requires adding a full LOM NIC chip and taking up precious PCIe lanes, instead of just adding a (much cheaper) LOM PHY.
It would be better if there was a way to allow retaining/updating microcode patches for errata, while eliminating all the other nonsense.
You can further update the processor microcode later, from UEFI or from the operating system. But the all-important initial processor microcode[1] update has to be done from a trusted path [for Intel SGX to be available].
And no, it is not UEFI early boot updating the microcode as it used to work in the past: when doing a secure Intel SGX boot path, the microcode looks up the FIT table in system FLASH, to get the address of a microcode update table in system flash. If found, the microcode then proceeds to self-update from FLASH.
This whole auto-load-microcode-from-FIT thing seems to have started with Skylake. Since Intel SGX is almost entirely implemented in microcode, it makes a lot of sense.
ON INTEL SKYLAKE AND LATER, you can notice whether the current microcode update came from FIT or not by reading its revision number. If it is odd, it came from the FIT. If it is even, it came from regular UEFI or O.S. updates.
https://review.coreboot.org/cgit/coreboot.git/commit/?id=504...
As for recent Intel systems without Intel SGX (or with it disabled), you still likely need a firmware-provided initial microcode update or it will be hopelessly buggy. Chances are it won't be stable enough to actually boot the target O.S.
[1] Intel has been shipping its processors with shamelessly incomplete/buggy factory microcode for a while now. You pretty much have to install a microcode update, or what you will get might not even qualify as a X86-64 compatible processor. The factory microcode doesn't need to know how to do paging or hardware-assisted virtualization correctly at all, for example, or even implement SIMD and floating point math instructions. All it has to do is to be able to run enough of BIOS/UEFI to get the initial microcode update.
Perhaps it would behoove people to run a "keyscrubber" daemon that constantly generates random numbers and AES-encrypts a few kb of data and sends it to /dev/null. _IF_ the ME is jotting down keys, and _IF_ there is only a finite amount of space for it to store them, such a daemon might be able to flush out real keys and overwrite them with junk to hamper any retrieval efforts.
Again, two big hypotheticals, but, if it were stealing keys, the buffer would have to be pretty small, otherwise people could eventually detect it changing sizes or hashes in NVM. I wouldn't expect such a thing in standard redable NVM anyway, it's probably on a die somewhere and only a few kb.
It would have to be Intel doing this. A lot of hackers have tried to write their own modules for the ME, but to my knowledge no one has been able to run one successfully. [0]
> _IF_ the ME is jotting down keys, and _IF_ there is only a finite amount of space for it to store them, such a daemon might be able to flush out real keys and overwrite them with junk to hamper any retrieval efforts.
There is. The ME on consumer systems has to fit within 1.5MB, and on corporate systems (e.g. servers) within 5MB. The only persistent storage the ME has accessible is the SPI flash (which has the above size constraints) or the TPM (if there's one installed). To my knowledge, the TPM can only be used to authenticate a secret once stored, you can't ever read it back from the TPM.
Otherwise, you'd have to have malware which runs inside the OS to receive the data from the ME and write or sends it somewhere else.
But really, why bother going for the ME? It has a root of trust burned into the PCH silicon, and it's obviously in Intel's interest to keep the signing keys very secret.
There's much lower hanging fruit if someone wanted to steal AES keys. Just install malware into UEFI or another controller (e.g. SSD, hard drive). This has already been documented in the wild, the source is speculated to be state-level actors (e.g. US, Israel). UEFI is handled by the OEM, which means they put the least amount of time/money into it as they possibly could.
Just search online for BIOS/UEFI password bypassing tools if you want a sample of how terrible OEM implementations are.
[0] http://www.slideshare.net/codeblue_jp/igor-skochinsky-enpub
Yes, and this is possible, though I would consider the possibility remote.
This would require collaboration between Intel and three letter agencies. Additionally, since the ME firmware is stored on SPI flash, anyone who suspected their ME might be eavesdropping could contact a researcher to dump their firmware for analysis. So I highly doubt Intel would be shipping this functionality in every ME firmware release.
Deployment would likely be targeted against a specific individual/group.
I'm not saying it couldn't be done, but the ME is not entirely a black box. The CPU architecture of the ME is known, the firmware can (and has been) dumped and analysed (though not all modules as some are encrypted).
So, it's a possible attack vector, the but effort required is much higher than building persistent UEFI malware. I don't think anyone would go to the effort to build an ME rootkit when they could just do it in UEFI.
thats part and parcel for any large US-based IT company these days.
> since the ME firmware is stored on SPI flash,
When you're Intel, you make the IC's and you can put whatever you want in there. If they were in bed with TLA's, I'd expect the pilfered keys would be stored in a sliver of NVM gates deep inside the die (in which chip, I can't say, perhaps in the CPU itself) (and probably encrypted with their own secret key). That's why I suggest that it would be easy to overwrite them just by constantly running aes with fresh random keys.
If you want to get into the speculation rabbit hole, it's far more fun to assume that instead of calculating something_truly_random(), RDRAND actually returns `AES-CTR(something_truly_random(), NSAKEY, counter)` as random output - which then becomes P & Q for your RSA keys. This'd be a far easier attack to mount, and wouldn't require any exfiltration of keys; just being able to see any current RNG state would expose all the previous states.
This might not be a problem for Linux, since RDRAND is mixed in, but for a while RDRAND was the exclusive entropy source for TCP sequence numbers, ASLR offsets, etc: https://cryptome.org/2013/07/intel-bed-nsa.htm
Who knows how Windows or OS X handles this.
wow, that's insidious. I'd never even considered something like that!