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Comment by luma | Hacker News Reader

Enabling it isn't generally easier either, and it can be secured with certificates on both side. Every time this topic is brought up I'm surprised by the number of people who think remote access is bad and cannot possibly be secured, while not actually digging into what it would take to compromise such a machine.

Maybe it's the server admin in me, but OOB BIOS-level remote access and management for my systems is a godsend and my biggest issue with it is that they tend not to include those features in their "enthusiast" chipsets.

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The security expert in me is terrified at the concept of remote access that, far too often, isn't actually managed very well. I've been to far too many places that have management interfaces like this and either don't know it, or don't apply updates.

It's not that remote access is bad, it's that all the remote access I've seen has been horrible. Hash disclosure is just seen as "meh, that's the way it is", and being able to login without a password is standard unless the IT has taken the time to update something they often don't even know about.

The features are included in all modern Intel CPUs AFAIK, if you found one where it wasn't included please let me know as its absence would be a feature for me.

As for the number of people who think remote access is bad, nobody seems to be denying it can be useful, but by baking it into hardware you're basically hoping that it doesn't get hacked. If it was an optional dongle nobody would care.

Exactly.

Optional, hardware mediated remote access is good.

The remote access part is called AMT[1] and is part of the Intel vPro[2] feature set. It most certainly is not enabled in all modern Intel processors. Further, it requires a compatible processor, chipset, and BIOS for it to be enabled.

There is a common misunderstanding in these discussions that the ME features of the Intel processor (included in nearly all modern procs) allows for hardware level remote access, which isn't true.

[1] https://en.wikipedia.org/wiki/Intel_Active_Management_Techno... [2] https://en.wikipedia.org/wiki/Intel_vPro

Yeah, right. I suppose we're just supposed to take their word for that. There's an enormous difference between the concepts of trusted and trustworthy. You're extremely naive or clearly never read anything Snowden released if you think 'trust us' is enough.

Are you suggesting Intel has implemented hidden backdoors into all of their systems?

Not OP but it could be very much possible and that's what OP is trying to say. Just taking it on Intel's word that they haven't done it is not the correct way to go. For the truly privacy minded, it's better to err on the side of caution.

Err on the side of caution in this sense would mean fabricating your own proc. Are you going to do that?

How do you know the fab you send your design to doesn't implement a backdoor? You have to have trust at SOME level.

That is exactly my point. If you don't trust Intel, then who are you suggesting should build your processor? Unless you are going to design and fabricate your entire system top to bottom, and have no other persons involved who could surreptitiously insert evil code, then you're going to have to accept some degree of trust in a 3rd party.

It's not just Intel you're trusting, it's the OEMs, who also have an EXTREMELY poor record. Just take a look at the ENORMOUS number up BMC and auto-update vulnerabilities. They really just either couldn't care less, or are deliberately making machines vulnerable. Things are being pushed into IME, that aren't optional, often aren't wanted by users (or snuck in there so they wouldn't know), don't all have to be there, can't be verifiably disabled or overriden by end users. Even if it weren't backdoored (unlikely), it presents an ENORMOUS attack surface at the very worst possible privilege level. Open source designs that are at least inspectable by researchers would be a start. But more importantly - allowing users to CHOOSE whether they want to override software (it IS after all software and not hardware). Why shouldn't we be permitted to run Libreboot etc on modern hardware and know that when we turn a machine off, that it's off, without unplugging network, power cables, batteries, etc?

How do you know the fab you send your design to doesn't implement a backdoor?

It really wouldn't be that hard to compare what you received from the foundry with the masks you sent them. There are services that decap ICs and attempt to reverse engineer them. Here's the first hit I found on Google: http://www.intelligservices.com/Services.htm

You wouldn't need the reverse engineering. All you would need to do is to compare that all the metal layers (and perhaps poly) match what you sent. That's an almost trivial comparison. The hard part of reverse engineering is in figuring out what the circuitry actually does, and you already know that, since it's your chip!

It could be possible for a fab to alter diffusion layers to change the functionality of a chip. That would be harder to detect by services such as the one I mentioned. But it would be very hard, very time consuming, to attempt to hack in a backdoor by only messing with base layers, rather than messing with metal or with poly (where changes are easily observed).

If there were to be a backdoor anywhere in a design, it would be in IP you used on your chip, that you got from either your foundry or from a 3rd party IP supplier. It would be easy enough to hide all kinds of stuff there.

AMT is full of holes too: http://people.kth.se/~maguire/DEGREE-PROJECT-REPORTS/100402-...

From what I've seen, Intel ME is the set of CPU features that supports applications such as Intel AMT. As Intel ME is built into all modern x86/x64 Intel CPUs, the possibility for exploiting Intel ME is still a security issue, even if some features aren't enabled by default.

To put it another way, what are some of the details that the author(s) of this article got wrong?

https://libreboot.org/faq/#intel

None, but you are taking away from it things that the article doesn't say. AMT is a subset of ME, it's not available on all procs, and even if it is available, it also requires the supporting chipset.

Nearly everyone reading this on a laptop/desktop system is doing so on an Intel processor. Go ahead and attempt to enable remote access without a supported proc/chipset/bios and then come back and complain about this unexpected remote access.

There is a lot of misunderstanding about this technology in the security world which strikes me odd because it's well-documented and readily available for your own testing.

True enough. But as I mentioned, I was rather terrified when I tried this on my thinkpad laptop. I'm sure many other business laptops have similar facilities (and yes, of course it is a feature to be able to manage a large fleet of machines, both work stations and servers).

As for trust, first, what we generally know is that any complex system is likely to have flaws. So any remote access system is likely a back door - intentionally or not. A physical off switch would be prudent (arguably switching off wireless network card and not connecting an ethernet cable is one option: but then your options are: no networking or possible vulnerability).

It's not as if any networked machine is "perfectly secure" - but it'd be nice to be able to set the scope of exposure even more easily, and granularly.

Second, one thing is trusting Intel to not intentionally install a back-door - keeping in mind that includes any "golden key" for updates. And not leaving any holes in the interface they expose (ie:getting the feature right). That in itself is a pretty high bar, imnho. But another thing is trusting Intel not to build in secret backdoors - that is; if they say, no, there's no IME in product X, then trust them on that. That is to me a much more trivial thing to trust. I know there will be bugs in the software and hardware, but I'm not all that afraid of maliciousness.

If I was working for a Chinese intelligence service the threat model might have been different.

In sum, given that there's bound to be bugs, and might be well-intentioned software upgrade support - I would prefer if it was easier to buy high-end parts without stuff like IME (this also applies to AMD btw) - or at least that it was easy to remove a jumper or toggle a dip switch to turn the stuff completely off.

[ed: finally re: server Vs laptop: there are some things that doesn't matter as much if it's exposed on a server: got my encrypted backups? Encrypted email? No problem. Got my secret key from my laptop? that is a problem]

TL;DR: Build yourself a desktop with a non-vPro CPU and a non-Intel NIC. Check [0] for a list of such CPUs.

The usual recommendation is to either get a pre-2009 AMD machine (which is what my present desktop is) or get a Sparc machine. My boss won't buy me a desktop with an UltraSparc CPU, so I won't bother with that. AMD has substantially less documentation than Intel, AFAICT, so Intel products deserve investigation for their relative starkness.

An albeit outdate list of systems to avoid, see [1].

I will assume that you are trying to build a desktop from off-the-shelf parts.

For sure, get a CPU without vPro, since that downgrades the type of AMT/IME feature set to Standard Manageability:

"Please note that NON -vPro™ Intel® desktop procesors will make Intel® ME FW to switch its features set from full Intel® Active Management Technology to Intel® Standard Manageability that do not suport Intel® AMT KVM Redirection feature (it is disabled internally in the Intel® ME FW)." [2] When the CPU doesn't support AMT, then Standard Manageability is what is running in the background.

This says 2 things: (1) non-vPro desktop CPUs downgrade AMT to Standard Manageability and (2) IME is active regardless of the CPU's feature set.

What is Intel Standard Manageability? "Q8: What is Intel® Standard Manageability and can it run on a non-Intel® vPro™ technology-based CPU? A8: Some basic management capabilities are available on non-Intel® vPro™ technology-eligible Intel® Core™2 processors as well as Intel® Pentium® dual-core and Intel® Celeron® processor-based CPUs. Intel® Standard Manageability is available only on desktop systems right now (not notebook), and only includes basic capabilities such as hardware and software inventory and remote diagnostics." [3]

I can't tell if Standard Manageability is a lite version of AMT. Intel's documentation on it [4] isn't a whole lot of help.

Intel mentions that Atom and i3 platforms generally do not support AMT. [5]

At the bottom of this [6] page lists those Intel chipsets with IME. I'd consider that to be a list of chipsets to avoid, but those cover almost all modern chipsets, AFAIK.

For sure, don't use any Intel NICs: "Adding another NIC will not nullify Intel® vPro™ technology verification, but Intel® Active Management Technology communicates only through the onboard network interface of Intel vPro technology, and it is strongly recommended that an additional wired NIC is not added to the platform as this might cause some of the features of Intel AMT to not operate as expected." [7]

[0] = http://ark.intel.com/search/advanced?s=t&VProTechnology=fals...

[1] = https://communities.intel.com/docs/DOC-2033

[2] = https://communities.intel.com/thread/65350

[3] = https://software.intel.com/en-us/articles/intel-vpro-technol...

[4] = https://software.intel.com/en-us/blogs/2009/03/27/what-is-st...

[5] = http://www.intel.com/content/dam/www/public/us/en/include/re...

[6] = https://www.kernel.org/doc/Documentation/misc-devices/mei/me...

[7] = https://software.intel.com/en-us/articles/intel-vpro-technol...

Can you enumerate "enthusiast" chipsets?

I'd like to know what chipset to choose in the future.

Thanks.

Yeah, I find it difficult to understand the hoopla around IME. It's not much different from the BMC that's on pretty much all server hardware.

Let me make this totally clear. The top OEM hardware manufacturers couldn't give a CRAP about your security.

https://duo.com/blog/out-of-box-exploitation-a-security-anal...

e.g. http://teletext.zaibatsutel.net/post/145370716258/deadupdate...

But you're totally fine that THESE are the people with unfetted power to fill your system with backdoors? (Not to mention NSA etc who'd almost certainly have access).

What's wrong with you having zero care about the world's data security?

It's not so much that I don't care, more that it's nothing new.

I just don't understand why people are suddenly railing against IME instead of Dell, SuperMicro, HP, etc when there is far more hardware out there with far, far less secure BMCs and it's been that way for ages. IME is probably closer to the best of the bunch as far as security goes.

IME is horrible and we should be railing against all horrible implementations. I can assure you I let my OEM know full well how I felt about insecure automatic update software (even though I wipe the system as soon as I get it, something I can't do with ME). I'll be taking my next purchase elsewhere. Unless people speak up, it's guaranteed to only gets worse.

I think we're talking about two different things. BMCs run separately from the rest of the system and are active even when the machine is halted. They provide remote mouse/keyboard/monitor, power control, remote device mounting, bios settings, hardware sensors and monitoring, etc. These have been in servers for ages, do the same thing as IME, and are way less secure. None of it has any relevance to software updaters or software at all really since a lot of these boxes are shipped without an OS or even hard drives.

I followed what you meant and understand baseband management controllers are more similar to IME in terms of risk profile. They're not (generally?) on-chip though, so it's at least up to individual OEMs, and purchasers have slightly more options (if slim). Agree it's not widely enough recognised either though. There's some coverage at least:

https://www.schneier.com/blog/archives/2013/01/the_eavesdrop... https://isc.sans.edu/diary/IPMI%3A+Hacking+servers+that+are+... http://arstechnica.com/security/2013/08/remote-admin-tool-im... https://www.usenix.org/system/files/conference/woot13/woot13... https://community.rapid7.com/community/metasploit/blog/2013/... https://www.schneier.com/blog/archives/2013/01/the_eavesdrop... http://www.websecuritywatch.com/authentication-bypass-vulner... http://fish2.com/ipmi/itrain.pdf

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