[HN Gopher] Secure boot certificate rollover is real but probabl...
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Secure boot certificate rollover is real but probably won't hurt
you
Author : zdw
Score : 83 points
Date : 2025-07-31 17:21 UTC (5 hours ago)
(HTM) web link (mjg59.dreamwidth.org)
(TXT) w3m dump (mjg59.dreamwidth.org)
| M95D wrote:
| > [...] systems that only trust the new certificate and not the
| old one would refuse to boot older Linux, wouldn't support old
| graphics cards, and also wouldn't boot old versions of Windows.
| Nobody wants that [...]
|
| EVERYBODY wants that! And I mean ABSOLUTELY EVERYBODY! Updates
| are now mandatory everywhere, in both Windows and Linux, and GPU
| manufactureres would LOVE to make the old cards obsolete, even if
| technically the new cards aren't much better.
|
| So expect to see the old certificate invalidated quickly and
| automatically, in the name of security, of course!
| michaelt wrote:
| Even if this did happen, there's a trivial workaround
| available: Just go into your BIOS and switch 'Secure Boot' off.
|
| Secure Boot is a fine thing if you're a huge corporation and
| want to harden laptops against untrustworthy employees, or
| you've got such a huge fleet of servers they go missing despite
| your physical security controls, or you're making a TiVo style
| product you want to harden against the device owners. But when
| the user is the device owner? Doesn't do much.
| trelane wrote:
| > you're making a TiVo style product you want to harden
| against the device owners.
|
| This sentence just makes me so sad
| observationist wrote:
| This should be illegal, and anyone caught doing it fined
| twice the total cost of amortized ownership per each device
| owner over the total duration of ownership in addition to
| completely refunding every customer.
|
| Throw in jail time for decision makers. Lets make markets
| honest with real incentives.
| necovek wrote:
| For a start, stop buying those products: vote with your
| wallet.
|
| Do you own a phone that's easily rooted? Who else does?
|
| What about your WiFi routers? Internet modem? AirTags?
| Smart home appliances?
| M95D wrote:
| You won't be able to switch it off for long. See how many
| phones still have that option! [1]
|
| In the end what matters is always money. Always.
|
| What brings more money? TiVo or buyer-owned device? You think
| 5% of technically competent potential buyers would make a
| difference when the 95% illiterate users will just replace
| the product no questions asked?
|
| It started as a fight against piracy and half-competent users
| that break their own systems (and the company's systems too,
| like you said). But slowly the industry sees that there's
| more money to be made if the same technology can provide a
| belivable argument in right to repair and planned
| obsolescence court cases.
|
| [1] https://github.com/melontini/bootloader-unlock-wall-of-
| shame
| II2II wrote:
| Get back to me when it actually happens, because I've been
| hearing that line for about 15 years now and it has not
| happened.
|
| The reality is that PC's address the needs of a
| fundamentally different market than "TiVo"s or even mobile
| phones. While most could, and probably should, be using
| secure boot noone seems to be eager to take away the option
| to disable it.
| supportengineer wrote:
| I'm surprised more huge corporations don't move towards a
| "Chromebook only" by default. Now you don't have to manage
| _anything_. We 're all doing our work in browsers anyway.
| keyringlight wrote:
| I think at some point there will gradually be a line that
| divides consumer type devices and Workstation with a
| capital W type devices. If nothing else it'll encourage the
| PC market to really decide for each use-case how much they
| value having a huge range of laptop or pre-built
| configurations or being able to assemble from parts.
| There's a lot of momentum in the PC mindset, but I also
| think a lot of people would be satisfied with less
| 'personal' so long as they were able to identify what they
| need and match it to capabilities of a model. 20 years ago
| the idea of a phone/table as the personal computer for most
| people and not a PC/laptop would be silly, yet here we are
| citizenpaul wrote:
| If you are issued a chromebook to me it signal that they
| consider you a replaceable cog.
|
| Its one of my interview questions these days. What device
| will I be issued?
|
| If its a chromebook I know that no matter what they say
| they don't really care about the postion.
| spydum wrote:
| There are quite a few who have. Ive worked in a google
| workspace enabled company on a chromeos device for like
| that last 6? Years. It works 95% of the things, but that
| last 5% can be frustrating: especially when it involves
| interoperability with a customers system. Now multiply that
| by 40000 employees.. that's a lot of help desk tickets.
| tux3 wrote:
| Go in the BIOS and switch it off?
|
| Certainly. Just one problem: Modern consumer BIOS interfaces
| are graphical and your GPU is off.
| ThePowerOfFuet wrote:
| That's not how it works; Secure Boot kicks in once EFI
| hands over control.
| mjg59 wrote:
| The driver that initialises your plug-in GPU is shipped
| in flash on the card, is signed by Microsoft, and won't
| run unless that signature validates.
| tpoacher wrote:
| Bitlocker
| mschuster91 wrote:
| > But when the user is the device owner? Doesn't do much.
|
| A decent Secure Boot implementation together with a BIOS/EFI
| password at least makes the life of US CBP or similar thugs
| wanting to use my devices against me much more difficult.
|
| And no, that's not an imaginary threat, certainly not under
| this administration which has come under fire multiple times
| for first detaining and then deporting random tourists.
| jimmaswell wrote:
| I certainly do not want old graphics cards to become ewaste for
| no good reason.
| dang wrote:
| Recent and related:
|
| _Linux and Secure Boot certificate expiration_ -
| https://news.ycombinator.com/item?id=44601045 - July 2025 (265
| comments)
| Arnavion wrote:
| There is also the option of enrolling your own certs and
| resigning the bootloader and any Option ROMs you need, if you're
| really worried / expect to actually be broken by this.
| mjg59 wrote:
| Re-signing option ROMs is not trivial (or, well, it's easy to
| do the signing, it's not necessarily easy to flash that driver
| back into the card)
| Arnavion wrote:
| I see. I've never had to deal with any Option ROMs myself. In
| that case the easier option is to add their hash to db?
| mjg59 wrote:
| That's the easiest, but it's a pain if you want to switch
| cards
| NelsonMinar wrote:
| This article notes that "nobody actually enforces these expiry
| dates". So this is another way that secure boot is proven to be
| nowhere as secure as it claims to be. Coupled with LogoFAIL and
| most hardware shipping with insecure debug keys.. has Secure Boot
| ever provided meaningful security? It sure causes all sorts of
| practical problems.
|
| https://arstechnica.com/security/2023/12/just-about-every-wi...
|
| https://arstechnica.com/security/2024/07/secure-boot-is-comp...
| OsrsNeedsf2P wrote:
| Was Secure Boot supposed to increase security? I thought
| Microsoft was using it to make it near impossible to install
| Linux
| mjg59 wrote:
| Linux distributions have been shipping with secure boot
| support since 2012, so if that was the goal it had already
| failed over a decade ago.
| michaelt wrote:
| It increases security in certain circumstances. Mostly for
| Windows users at big corporations.
|
| For example, you want your users' laptop hard drives to be
| encrypted - but also you have users who regularly forget
| their passwords? With bitlocker their hard drive can decrypt
| itself, so they only need to remember their windows login,
| which you can reset remotely.
|
| You give laptops to your field workers, who have full
| physical access and would love to play video games or access
| netflix when work puts them in a hotel over night with
| nothing to do? With secure boot you can keep your precious
| spreadsheets locked down, even if they're willing to boot
| from USB sticks or swap the hard drive.
|
| And perhaps most importantly, it has "secure" in the name. So
| the corporation's IT security auditors will like to see it
| turned on even if they have only a vague understanding of
| what it does.
| strstr wrote:
| With the default key hierarchies, the benefit is more limited.
| It raises the bar. Implementing known vulnerabilities takes
| work. And not ever configuration is vulnerable to every issue.
| And, for a lot of the vulns, the OS vendor shoves things in the
| dbx to mitigate.
|
| With custom hierarchies, it's a bit more compelling. But it's a
| lot of work to maintain.
| mjg59 wrote:
| The rollover coincides with stronger security policies for
| signed objects (enforcing code being read-only, that kind of
| thing) and people with stronger security requirements can
| remove trust in the old certificate to enforce that.
|
| Code has bugs. There's any number of critical vulnerabilities
| in Linux, Windows, MacOS that have allowed bypass of all
| security features - does that mean all security features remain
| security theatre?
| armada651 wrote:
| They clearly didn't want to leave a system unbootable because a
| certificate expired. In which case you would have no
| opportunity to update the certificate because you can't boot
| the system anymore.
|
| They could've used a time stamping service to include a signed
| timestamp in the binary to compare the expiry date against, but
| that still leaves the system unbootable after the time stamping
| certificate expires in the far future.
|
| Besides, a hacking group powerful enough to steal Microsoft's
| Secure Boot private key will likely be able to steal a
| timestamping private key from a certificate authority as well.
| TacticalCoder wrote:
| Can someone knowledgeable on the subject explain if I understand
| the following right: - on a mobo the
| motherboard provider signs the PK - there's only one PK
| - the PK signs one or more KEK, like "Microsoft Corporation UEFI
| CA 2011"
|
| If that understanding is correct, can I add myself the new
| "Microsoft Corporation UEFI CA 2023" (the one that expires in
| 2038: I think that its name) the same way I can enroll new keys
| in the dbx? (say my own signed keys?)
|
| If I add the new Microsoft key myself, shall it be as a KEK or in
| the dbx?
|
| Will motherboard manufacturer release new firmware, with the new
| Microsoft key already signed? In that case, shall be a KEK ?
|
| Basically instead of thinking, as TFA suggests: _" Let's not
| worry about anything, everything shall be fine and keep working
| because keys expiration date aren't enforced"_, can I pro-
| actively enroll the new Microsoft key myself?
|
| P.S: I don't drink the SecureBoot kool-aid but something has to
| be said about having a Linux unikernel (kernel+initramfs) signed
| and enforced by SecureBoot. And SecureBoot does at least somehow
| work. Source: I modified on bit of my kernel and had a SecureBoot
| error and the kernel refused to boot. You can try it for
| yourself.
| mjg59 wrote:
| Vouched for the parent because it's a reasonable question.
|
| As well as the new root certificates in db, which are used to
| decide whether signed code will execute or not, there will be a
| new signed Microsoft key for KEK. This isn't involved in the
| boot process, but is required for Microsoft to be able to sign
| further revocation updates. The article is discussing the db
| case, and if you want to ensure things signed only with the new
| key will boot on your system, you would want to add them to db.
|
| Microsoft can sign a db update themselves (since there's a
| valid Microsoft key in KEK and db updates need to be signed
| with a key in KEK), but KEK updates need to be signed with PK.
| Microsoft doesn't own PK, so adding the new KEK requires the
| system vendor produce an update signed with their PK.
|
| If you are in a position to enroll the new keys then you should
| enroll the new db keys if you want new binaries to be
| guaranteed to boot, and add the new KEK if you want to be able
| to apply future Microsoft-signed dbx updates.
| fennec-posix wrote:
| yeah, that sounds about right for UEFI
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