alt Hacker NewsHaving spent a while working in embedded and learning that this is not a lesson that's been internalised: this is why you never sign any executable that can boot on shipped hardware unless you'd be ok with everyone running it on shipped hardware. You can not promise it will not leak. You can not promise all copies will be destroyed. If it needs to run on production hardware then you should have some per-device mechanism for one-off signatures, and if it doesn't then it should either be unsigned (if fusing secure boot happens late) or have the signature invalidated as the last thing that happens before the device is put in the box.
A lot of companies do not appear to understand this. A lot of devices with silicon-level secure boot can be circumvented with signed images that have just never (officially) been distributed to the public, and anyone relying on their security is actually relying on vendors never accidentally trashing a drive containing one. In this case Nintendo (or a contractor) utterly failed to destroy media in the way they were presumably supposed to, but it would have been better to have never existed in this form in the first place.
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I don't like this advice because it seems like it's only useful to people who want to do tivoization in the first place. I hope people who try to do that keep failing at it, because "success" is bad for the rest of us.
I think they _might_ have thought a little farther than this; as far as I can tell this tool was _supposed_ to only boot images with the same security checks as the actual fused state of the console, and the issue was that the section header parsing code was vulnerable to a trivial attack which allowed arbitrary execution, which of course could then bypass the lifecycle state checks.
I'd extend your thesis to "you need to audit your recovery tools with the _exact same_ level of scrutiny with which you audit your production secondary bootloader, because they're effectively the same thing," which is the same concept but not _quite_ as boneheaded as you suggest.
Recently, I see this class of exploit more commonly, too: stuff like "there's a development bootloader signed with production keys" has gone away a little, replaced with "there's a recovery bootloader with signature checking that's broken in some obvious way." Baby steps, I guess...