I understand problem of still-valid certs after domain expiration, but mere rotation strikes me as similar to password rotation ... which is currently discouraged.
Servers get compromised sometimes, people do stupid things with keys, etc.
We dont have a really good way of revoking keys after something bad happens. We have some bad ways, but they kind of suck.
An additional reason might be making it easier to punish a misbehabing CA (CAs are often too big to fail, you cant ban them without breaking half the internet)
Why would there be. If the key is 'revokable' that is a weakness in it self.
???
Why?
At least perceived censorship risk is why the archive.is guy always uses HTTP links and not HTTPS links for his site, iirc.
I don't really get the argument behind using HTTP links to avoid the censorship risk with HTTPS - just provide both and get the best of both worlds. Also, using HTTP is far more prone to being interfered with in transit - I recall BT (or their ISP business department) trialling that and injecting adverts into HTTP pages. I can't recall any instance of HTTPS being censored by restricting certificates.
The majority of CAs are in the US.
I guess it decreases the lead time of censorship. That seems pretty minor though.
What??
This does not make sense. Keys are revocable in most crypto systems.
Ish. The threat of that is part of a different risk model, and probably less serious.
A long-lived certificate that ends up being able to be used by a malicious party (perhaps due to a leak of the private key) could be serious for many users if the certificate can't be reliably revoked, which they currently can't be.
A mistaken or malicious revocation if someone were to manage that could be an issue to the service operator (users can't get in) but this is a safer failure than users connecting to a malicious shadow service due, for example, to an accidentally exposed private key and a DNS poisoning attack.
As others have mentioned: if revocation worked better currently, this would be less of an issue.
A few older crypto mechanisms were designed around trusting one thing totally. For example, everything's secure until the end of time provided that the user keeps a private key totally private at all times, with no interruption, ever, and if the user lapses then the overall mechanism breaks really badly.
They were complicated mechanisms held together by a screw made of a metal which was assumed to be infinitely strong.
The current fashion is to trust thing in a more limited way, and to design systems such that they won't blow up spectactularly if something breaks. Being able to revoke keys is part of that, it is a weakness that helps to avoid a really bad weakness.
For example, some sites were closed and we asked the site owner to revoke their cert. We got "What does that mean ?", they had lost their private key.
Also other departments had certs that expired, they had no idea what to do. I left over a year ago, and someone who knows more about certs that I do left not long afterwards. I know many certs are due expire soon, good luck to them.
The point of this is I can see 45 day certs being a huge issue for that company. When I left they were looking into non-expiring certs. I have no idea what they ended up doing.
FWIW, this is a fortune 500 company.
But to set it all up in F500 size company, that is totally different discussion and not only TLS certs but all kind of other cert auth that happens there.
* Certs come with secrets. Long-lived secrets are riskier than short-lived ones because of window of opportunity if they're compromised in an undetected way.
* Less frequent cert rotations mean that the rotation process is inherently riskier. The old adage of "request a 2-year cert, and you're scheduling an outage 2 years from now" has a lot of truth to it. More frequent rotations increases the incentive to automate, which reduces the service risk.
Personally, I don't see the problem with short expiry dates, though less than a month would be too short in my opinion.
Their users are "people using browsers", not "people asking for cert signatures".
Plus, this concept that short expiration times increase security is suspect at best. If the private key leaked, 45 days is far too long, you'd need to reduce this to hours to actually help as a revocation strategy. And even then, chances are that the new key will leak as well right away, as it's most likely that the key was stolen by some undetected malware. And if the key didn't leak, a two year old cert is just as secure as a two minute old one.
I disagree. The smooth running and ease of automation of TLS certs benefits the entire ecosystem, including the end-users. Remember when the only sites that had TLS certs were the ones that could afford it?
> If the private key leaked, 45 days is far too long, you'd need to reduce this to hours to actually help as a revocation strategy.
This is a good example of the Nirvana Fallacy.
> And even then, chances are that the new key will leak as well right away, as it's most likely that the key was stolen by some undetected malware.
No certificate expiry control can protect against continuous, undetectable data exfiltration. Meanwhile, a one-time access that grants me the ability to impersonate you for 2 years is a significantly worse situation than one that only grants me that ability for a few weeks.
Privilege escalation and Dev Ops rot. Long-lived certs often get compromised when privilege escalations happen and someone gets access to an account or computer that has private keys on it.
One example scenario for privilege escalation: let's say a hacker gets access to one of your employee's or vendor's machines and associated accounts using a zero-day, or phishing, or some other method that goes undetected for some time. The attacker, as part of this attack, successfully gets access to your cert's private keys through some way or another without drawing attention to themselves.
Some time later, your firm makes several security updates. When doing this, you unknowingly patched the attacker out of your network. The attacker is now in a race against time if they want to do something with the cert before it expires, and in this kind of situation, the sooner that cert expires, the better, because the attacker gets less time to do something with it. In a perfect world, the cert expired exactly when they got patched out, but because we're not guaranteed to know if there's an attacker in the first place, "keeping the expiration time as short as is reasonably possible without impacting service reliability" is what things seem to be moving towards, to limit the blast radius during access leaks.
As for Dev Ops rot, speed has a tendency to change requirements in favor of automation. Generally, certificate rotations tend to be a pain point - they break management panes, they take down websites, they throw browser errors, they don't get updated in pipelines, and other woes happen when they expire that demand people keep track of a ton of localized knowledge and deadlines that's easy to lose or forget. However, paradoxically, the longer the time between rotations, the more painful they tend to be, because once rotations are sufficiently fast, it becomes unmanageable to do them manually: demanding speed forces people to build anti-fragile rotation systems. Making the requirement be shorter is in some sense an attempt to encode into managerial culture "you need to automate this", as a bulwark against swapping your certs out being anything besides automated or one click rotations.
A leaked password will reveal itself to the authority when used. You have to connect to something to use it and when doing so, can be flagged.
A long lived certificate and key can be used with no interaction with the authority, so how do you know that it is being used maliciously? The renewal is the interaction with the authority which could pick up malicious activity, so making it more regular is beneficial.
It is like credit cards. The more problem the more money is to be made by middlemen.
And I could argue that lower prices implies money is made somewhere else. Like how Cloudflare infested half the internet with their free MITM.
But, ye, I should chill a bit on topics like these. I have hard time not ending up in a 'Google etc. is coming for me' rant.
It's particularly bad to do this when you're knowledgeable and (let's assume) correct on a topic, because then the bad parts of your comment (such as personal attacks) end up discrediting the truth. That doesn't help anyone. https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...
The hope is that 45 day certs don't require consultants because if you don't set it right you'll find it right away... and of course the risk of leak is much lesser.
If you'd rather pay someone else to do it for you, then that's your own issue and not really anything to do with the length of certificate validity.
Cargo culting strikes again. Forcing password rotation is bad because it causes people to choose passwords with a given pattern (eg. password1, password2, etc.), which defeats any security benefit. Rotating certificates have no such issue, because the key is (presumably) randomly generated.
Additionally, short renewal periods encourages automation which is more secure than a manual process.
Password rotation is discouraged because usually it means that users will create weaker passwords.