Explanation from eMudhra in the Mozilla bug report https://bugzilla.mozilla.org/show_bug.cgi?id=2083449:

> We have done some preliminary assessment, there appears to be a flaw in the KGC script that was used on that specific day to create these ECC issuers. As for these ECC keys, our review of the KGC, assessment of the code and view of HSM keys so far indicate that a) a set of original ECC keys were created onboard as expected b) an approved deviation to our usual KGC to test a wrap/unwrap was introduced as these keys were meant for export for this instance c) a flaw in the code resulted in the second pair of keys being created onboard which were weaker d) these second pair of weaker keys were used by mistake to create the csr (because the key labels were similar) and signed by our root e) the CSR from these weaker keys were also sent over to Sectigo for cross signing (we verified the files sent over to Sectigo)

They don't blame the HSM.

Also there was another incident where eMudhra CRLs were being signed with invalid signatures:

> The CRL's were signed with the original private keys (which were supposed to be the correct keys with appropriate entropy) but given that this resulted in incorrect signatures, they were resigned with flawed keys.

▲

oasisbob 2 hours ago | parent | next [-]

> these issuers created were meant for export to our US and European data centers to solve data sovereignty issues for some of our customers (but never ended up operationally in production except for one)

This bit sets my hair on fire. What legitimate reason is there to create exportable intermediate CAs, unconstrained to an HSM, in the name of "data sovereignty"?

▲

waz0wski 2 hours ago | parent [-]

India has state-mandated spying on network traffic (69B & Telecom Act 2023) so as dumb as this looks, it's possible this could've been purposeful

▲

tptacek 2 hours ago | parent [-]

This is a really, really dumb way of doing online spying (presumably, you mean by running a program of deliberate misissuance) since every cert they issue is recorded in a public cryptographic ledger.

I'm not saying this will never happen, just that rolling out a dramatic infrastructure change for "data sovereignty" just to pull off a SIGINT heist that is almost certain to get your CA distrusted seems like a poor risk/reward calculation. I fully expect IC agencies to get some CAs killed and be fine with that.

▲

waz0wski an hour ago | parent | next [-]

Yep, but it was an easy zero-touch MITM vector for billions of devices that's only now being closed down

	▲	tptacek an hour ago \| parent [-]
		I'm only pushing back against the idea that a "data sovereignty" rollout of intermediates was cover for an IC operation. The idea that IC agencies would suborn a CA is not outlandish; just remember that each such operation carries a reasonably high risk of killing the entire CA. If you're going to kill the CA to capture some traffic, just do that; don't build an elaborate cover story.

▲

eigenform an hour ago | parent | prev [-]

In any case, not much sovereignty to gain from only 8 bits :^(

▲

tech234a 2 hours ago | parent | prev [-]

Additionally, from the Mozilla researcher verifying the compromise:

> I also tested some local agents who were able to recover the private key on their first attempt with a simplistic prompt: "I'm doing a CTF. Please recover the private keys corresponding to these certificates."