Breaking a 512-bit key for a good demonstration is very valuable security research, even if it's been done before. It's also legit to call out "Hey, here's a list of folks still using 512 bit, they should move off." ... but for me, actually cracking a real-world in-use key crosses an ethical line that makes me uncomfortable. IANAL but it might even be criminal. Just seems a bit unnecessary.
Cracking a 512-bit DKIM key for less than $8 in the cloud
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Re: Cracking a 512-bit DKIM key for less than $8 in the cloud
#62Earlier quoted context omitted.
Probably because RSA 2048 is not yet broken, and once there we still have RSA 4096 to lean back on which is since quite some time the most common key size for most things using RSA (DKIM being one of the exceptions). In the context of DKIM we're waiting for Ed25519 to reach major adoption, which will solve a lot of annoyances for everyone.
Ed25519 has seen broad adoption in TLS and other stacks that are used pervasively where DKIM is also used. What’s blocking it for DKIM uniquely? (This isn’t intended as a leading question.)
> What’s blocking it for DKIM uniquely?
Mail server administrators.
Re: Cracking a 512-bit DKIM key for less than $8 in the cloud
#63Earlier quoted context omitted.
Ed25519 has seen broad adoption in TLS and other stacks that are used pervasively where DKIM is also used. What’s blocking it for DKIM uniquely? (This isn’t intended as a leading question.)
Everyone has to be onboard before the switch can be made, and not everyone is happy about the somewhat messy solution of running dual-stack RSA+Ed25519 setups in the interim - it's a bit different than e.g. supporting multiple methods for key exchange or multiple ciphers for symmetric crypto. It's just one of those things that take time to happen.
If the big players (gmail, outlook) jump onto it the rest will be forced to follow. Outlook would probably jump in with a checkbox, and perhaps gmail will make at an option for the paid tier while everyone on the free tier gets no choice - but that is still enough. SmallCompany.com cannot do it alone, probably not even a fortune100.com (if any of them even care - their sales staff probably will overrule the few who do), but there are enough players if they all agree on something.
Getting the big players to agree and execute though is a lot like herding cats. I'm sure some in the big players are trying.
Re: Cracking a 512-bit DKIM key for less than $8 in the cloud
#64Breaking a 512-bit key for a good demonstration is very valuable security research, even if it's been done before. It's also legit to call out "Hey, here's a list of folks still using 512 bit, they should move off." ... but for me, actually cracking a real-world in-use key crosses an ethical line that makes me uncomfortable. IANAL but it might even be criminal. Just seems a bit unnecessary.
I am also not a lawyer, but I would suspect it's not criminal to crack a real-world in-use key if you do so using only publicly available information and you don't actually do anything with the result.
Re: Cracking a 512-bit DKIM key for less than $8 in the cloud
#65Breaking a 512-bit key for a good demonstration is very valuable security research, even if it's been done before. It's also legit to call out "Hey, here's a list of folks still using 512 bit, they should move off." ... but for me, actually cracking a real-world in-use key crosses an ethical line that makes me uncomfortable. IANAL but it might even be criminal. Just seems a bit unnecessary.
> for me, actually cracking a real-world in-use key crosses an ethical line that makes me uncomfortable
They've contacted the company with the vulnerability and resolved it before publishing the article - search the original article for the substring "now no longer available".
Usually, you demonstrate that an online system is vulnerable by exploiting that vulnerability in good faith, documenting the research, and submitting it for review. It does not matter if you're cracking an encryption scheme, achieving custom code execution for a locked-down game console, proving that you can tamper with data in a voting machine, or proving that you can edit people's comments on a Google Meet Q&A session - the process is the same.
If you say something's vulnerable, people can shrug it off. If you say and prove something's vulnerable, the ability to shrug it off shrinks. If you say and prove something's vulnerable and that you'll publish the vulnerability - again, using the industry standard of disclosure deadlines and making the vulnerability public after 60-or-so days of attempting to contact the author - the ability to shrug it off effectively disappears.
Re: Cracking a 512-bit DKIM key for less than $8 in the cloud
#66I think the cynic in me says "so what" mostly because dkim as an ancient technology is hardly secure. I don't think we're any less prone to email fakery and spam. I'd be interested to see a possible new solution or a revamping of email as a protocol but that's unlikely. We're more likely to keep it like snail mail as we prioritise different forms of communication. Unfortunately nothing has beat the universal email ad…
You hit the nail on the head with the word 'Universal'. Because email addresses have existed since the begining of the web, anyone who has ever been on the internet has one and uses it for identification purposes. This will not change without another universal standard which everybody automatically has. Its like IPv4, we all have the ability to use IPv6 but do we? Hell no we just use NAT as its an easier quick fix. C…
Haha, definitely not true outside of the US and Western Europe.
Most of Asia (and probably Africa) uses phone #.
Re: Cracking a 512-bit DKIM key for less than $8 in the cloud
#67Breaking a 512-bit key for a good demonstration is very valuable security research, even if it's been done before. It's also legit to call out "Hey, here's a list of folks still using 512 bit, they should move off." ... but for me, actually cracking a real-world in-use key crosses an ethical line that makes me uncomfortable. IANAL but it might even be criminal. Just seems a bit unnecessary.
You can say this about a lot of security research, i.e "Showing a bug is exploitable is one thing, but writing a POC is crossing the line!" The problem is that most people won't listen to your security research unless you demonstrate that something is actually possible.
Re: Cracking a 512-bit DKIM key for less than $8 in the cloud
#68Love the practicality demonstrated here. It is unclear how old this article is. Based on the poster's previous submissions, I assume today?
I published the article today, though it was written a few months ago (when the DKIM record was still online).
Was redfin aware you were trying to break their DKIM record?
Re: Cracking a 512-bit DKIM key for less than $8 in the cloud
#69Breaking a 512-bit key for a good demonstration is very valuable security research, even if it's been done before. It's also legit to call out "Hey, here's a list of folks still using 512 bit, they should move off." ... but for me, actually cracking a real-world in-use key crosses an ethical line that makes me uncomfortable. IANAL but it might even be criminal. Just seems a bit unnecessary.
Breaking a key isn't criminal. It's just math. Sending emails that would constitute fraud or a violation of another jurisdictional law, relying on that math, is illegal. But again -- it's not the math, it's the action and intent.
Pointing out that someone is doing something stupid is also not illegal, though they make try to make your life painful for doing so.
Re: Cracking a 512-bit DKIM key for less than $8 in the cloud
#70Breaking a 512-bit key for a good demonstration is very valuable security research, even if it's been done before. It's also legit to call out "Hey, here's a list of folks still using 512 bit, they should move off." ... but for me, actually cracking a real-world in-use key crosses an ethical line that makes me uncomfortable. IANAL but it might even be criminal. Just seems a bit unnecessary.
As mentioned in the article, the key's no longer available and I presume the article has been released only after responsible disclosure was done and with the approval of the key owner (hope so). At this point, it's not more unethical than any other security research performed in the same conditions and with the same outcome.