On Tuesday, August 29, 2017 at 12:25:51 PM UTC-4, cooloutac wrote:
> On Tuesday, August 29, 2017 at 11:38:59 AM UTC-4, Patrik Hagara wrote:
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> > On 08/29/2017 04:50 PM, [email protected] wrote:
> > > Leo Gaspard,
> > > 
> > > I have read about AEM but have never used it, it seems like it is
> > > geared towards protecting from USB's with malicious firmware on
> > > them.
> > > 
> > > Does AEM actually verify the integrity of /boot before using?  This
> > > is what I am looking for, either a method of encrypting /boot or
> > > even better, a secure method to verify its integrity during boot
> > > 
> > 
> > AEM does verify the integrity of /boot using the TPM seal/unseal
> > operation. If any of the boot components change, AEM falls back to
> > regular, unmeasured boot -- the user is expected to notice this and
> > cease using the potentially-compromised system (the lack of explicit
> > indication of failed AEM boot is deliberate, see the last FAQ item at
> > [1]).
> > 
> > The security provided by AEM is much more stronger than encrypted
> > /boot could ever offer, because as already pointed out, there is
> > always a little first-stage bootloader stub on the disk unencrypted
> > and it would be easy to overwrite it with a malicious version that
> > would intercept the encryption passphrase and exfiltrate it using eg.
> > unused disk sectors.
> > 
> > If someone did the above with AEM, the TPM would refuse to useal the
> > AEM secret as the platform state would be different.
> > 
> > The feature protecting dom0 from malicious USB devices [2] serves a
> > different purpose and is not related to AEM. Plus, you always need to
> > disconnect all untrusted USB devices while rebooting Qubes, regardless
> > of whether you have USB qube set up or not.
> > 
> > 
> > Cheers,
> > Patrik
> > 
> > 
> > [1] https://blog.invisiblethings.org/2011/09/07/anti-evil-maid.html
> > [2] https://www.qubes-os.org/doc/usb/
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> 
> my problem is unfortunately i can't keep buying new pc's. SO maybe its all 
> for naught for me.. Also AEM does not seem as reliable as secureboot. Alot of 
> issues on threads with some people. It seems complicated. even false alarms. 
> But I really do think they are supposed to compliment each other.  trusted 
> boot and measured boot yes? AEM definitely comes in handy for people who 
> would find it nescessary to buy new equipment.  
> 
> But I would still want an encrypted boot, if I was going to use aem,  and key 
> on a external usb disk,  which unfortunately means I could not use a sys-usb. 
>  Am I wrong about this?  Does this change in 4.0?
> 
> So this is where the what fits into you "security model"   What are you more 
> concered about. I assumed we had to choose between aem  vs sys-usb?  For 
> people travelling with laptops in strange places where physical compromise is 
> more likely aem is a good option.  Some people would prolly not just buy a 
> new laptop but know when to destroy theirs too lol.

Doesn't everyone destroy hdd's and phones when they bricked our outdated and 
you done with them like Hillary?  I always tell myself i'm going to and just 
have them stacked in a box,   cause nothing really that sensitive on there.  
But I feel it should be good common practice.

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