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ThinkPwn: System Management Mode arbitrary code execution

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Re: ThinkPwn: System Management Mode arbitrary code execution

#91
> First is the FCC vs WIFI channel selection in firmware. They want the choice to interfere be removed from the user in this occasion.

Fuck 'em.

> Second is cell carriers are not wild about unknown basebands conversing with their networks.

Fuck 'em.

> In theory the network should defend against bad phones but they'd rather not test that.

... hard.

Re: ThinkPwn: System Management Mode arbitrary code execution

#92
post #6

Earlier quoted context omitted.

I think this exploit requires local administrative access. If an attacker already has this, you're pretty screwed to begin with. In other words, while this could definitely make an attack more damaging and harder to remove, it doesn't seem like a reason to stop using a computer that has decent software and physical security.

This exploit just requires physical, not administrative, access to the machine. You build an EFI "app", put it on a flash drive, and execute it from the UEFI shell.

Well, physical access ranks higher than administrative. If an attacker has physical access, no system is secure, if only because the interface to the system is no longer.

Re: ThinkPwn: System Management Mode arbitrary code execution

#93
post #89

I wish we could even purchase machines without SMM, Intel Management Engine, and similar features. On any machine I own, I want the CPU and the software running in ring zero to be the last word on what happens. I don't think it's unreasonable to ask for a system that meets this requirement.

I think you were there during the Win8 period when UEFI secure boot and ACPI BGRT was introduced for example, right?

Yep.

Re: ThinkPwn: System Management Mode arbitrary code execution

#94
post #89

Earlier quoted context omitted.

I think you were there during the Win8 period when UEFI secure boot and ACPI BGRT was introduced for example, right?

Yep.

ACPI BGRT seems to be poorly designed for example. It probably should have been a UEFI boot service call not an ACPI table.

Re: ThinkPwn: System Management Mode arbitrary code execution

#95
post #64

Earlier quoted context omitted.

Although you are correct, I don't feel it's bad to blame the vendor who was running code that they didn't know the source of, nor the reasoning behind it's existence.

So, literally every vendor? Can you think of a single example of a vendor not running UEFI code from others, not running either Qualcomm's kernels for ARM chips, nor distributing Intel's ME firmaware, nor distributing AMD's TPM firmware? I don't think there's a single OEM that knows what they're actually running – if there is, SAMSUNG would likely be it, because they have a chance at actually doing everything in-hous…

I thought that Chromebooks, at least, run coreboot rather than UEFI, and so should be immune from this.

Re: ThinkPwn: System Management Mode arbitrary code execution

#96
post #77

This should be good news for people looking to getting rid of Computrace, effectively a rootkit, from surplus Thinkpads. http://forum.thinkpads.com/viewtopic.php?t=114641 Yes, I bought a surplus Thinkpad (T61) and found it had Computrace activated on it. Grrrr. Yes, I could call the Absolute(R) Software number and they should disable it for me. I have not been willing to sit on hold and jump their hoops to date. Sinc…

I dislike the arms race against laptop theft. It is not as much talked about as encryption backdoors, but...

Re: ThinkPwn: System Management Mode arbitrary code execution

#97

Earlier quoted context omitted.

As I commented elsewhere, we can, see https://news.ycombinator.com/item?id=12037410

That's good to hear. Thanks!

Note that I mentioned how it does not do any microcode updates though. I blogged http://yuhongbao.blogspot.ca/2015/06/why-your-core-2-process... about a problem that can prevent 64-bit Win8.1 from installing. I think you were there back then too, right?

Re: ThinkPwn: System Management Mode arbitrary code execution

#98
post #64

Earlier quoted context omitted.

Although you are correct, I don't feel it's bad to blame the vendor who was running code that they didn't know the source of, nor the reasoning behind it's existence.

So, literally every vendor? Can you think of a single example of a vendor not running UEFI code from others, not running either Qualcomm's kernels for ARM chips, nor distributing Intel's ME firmaware, nor distributing AMD's TPM firmware? I don't think there's a single OEM that knows what they're actually running – if there is, SAMSUNG would likely be it, because they have a chance at actually doing everything in-hous…

I wonder what command and control systems that ship with Russian and Chinese military equipment use.

Re: ThinkPwn: System Management Mode arbitrary code execution

#99

I wish we could even purchase machines without SMM, Intel Management Engine, and similar features. On any machine I own, I want the CPU and the software running in ring zero to be the last word on what happens. I don't think it's unreasonable to ask for a system that meets this requirement.

As I commented elsewhere, we can, see https://news.ycombinator.com/item?id=12037410

Old, outdated, expensive hardware with low specs? Nope. I have a lot of respect for what they do but it's not the solution we need.

Re: ThinkPwn: System Management Mode arbitrary code execution

#100

Earlier quoted context omitted.

This exploit just requires physical, not administrative, access to the machine. You build an EFI "app", put it on a flash drive, and execute it from the UEFI shell.

Well, physical access ranks higher than administrative. If an attacker has physical access, no system is secure, if only because the interface to the system is no longer.

its not longer fair to call game over with physical access;

indeed countermeasure like full disk encryption, computrace and Mac firmware passwords are all examples of things we do to raise the difficulty for a physical attacker.

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