6 ms·

Krebsonsecurity.com has an expired SSL certificate

74 points by k_sze 6y ago

dildozer 6y ago
It is a different Krebs, but still ironic
- dboreham 6y ago
  Other way around no, the Krebs in the news is the different Krebs?
  - dildozer 6y ago
    Yes Chris Krebs was fired, Brian Krebs is krebsonsecurity, no relation
dboreham 6y ago
Assume this is deliberate, since real domain hijackers would use a valid cert. Also helps to ensure browser vendors don't disable cert validity bypass. Very clever.
- lozaning 6y ago
  Based on his tweet it sure seems like he forgot to renew, and this isn't some kind of genius move to keep anyone honest. https://twitter.com/briankrebs/status/1328863446105010177 https://twitter.com/briankrebs/status/1328863446105010177
  - panarky 6y ago
    That tweet says "Despite what the browsers may be saying, the site is still safe to visit." Is it though? Asking people to ignore browser warnings seems like bad advice from a security expert.
    - k_sze 6y ago
      Yeah, I, too, found that to be a really odd piece of advice from a security expert. If I were the Brian (but I'm not), I would have asked followers to not trust the site until the certificate issue is fixed, even though I "know" my site is still safe. I think the properly cautious attitude is to consider all bets being off when a certificate is invalid for whatever reason. There is no guarantee what your visitors are actually getting.
      - marta_morena_28 6y ago
        Bias finds its way into every corner. And no, it's not safe unless you do some extensive analysis of the certificate in question. Is this actually a valid/genuine certificate, besides the timestamp? A normal user will have a hard time verifying that.
    - Mathnerd314 6y ago
      It's safe considering the threat model: the worst his site has seen is some DDOS attacks. With a MITM his site might end up hosting a 0-day, but hijacking is unlikely to begin with due to how low-profile his site is (outside of tech circles). And they'd have to attack DNS as well as his certificate.
tvbuzz 6y ago
Fake news designed to cut down on DDOS
ludditetech 6y ago
Chuckle, happens to the best of us - obviously.
- k_sze 6y ago
  I'm surprised that Brian Krebs still uses Comodo. Why not LetsEncrypt with automated renewal?
  - mpd 6y ago
    While you're not paying for the cert, there is certainly still a cost involved.
    - nkozyra 6y ago
      I would say the technical hurdle is about equal to comodo. What other cost is there?
      - mpd 6y ago
        Comodo is a renewal and updating an artifact (i.e. the actual cert), then you're done, vs. having to handle LE's API to deal with doing it 'automatically' and then carrying that forward. My point is simply that the cost is not zero.
        lights0123 6y ago
        You can still just replace the cert manually like you would any other CA. It's just there's no official GUI to do it with LE and you have to do it more often.
        jasonpeacock 6y ago
        There's already mature, widely adopted tools like certbot and acme.sh that do this automatically for you. It may not be zero, but it's no more than Comodo.
    - corytheboyd 6y ago
mehrdadn 6y ago
I never understood why browsers don't just go ahead and load websites with expired certificates and merely provide milder warnings for a few weeks/months. The expiration date doesn't mark any meaningful real-world event that indicates the private key might be compromised... it's just an expiration date. Why set off all the alarms and make the user freak out and make it so hard to visit the site as soon as the certificate becomes 1 millisecond too old? It seems to violate common sense.
- whoisjohnkid 6y ago
  That would open a new vector of attack where an attacker would simply have to compromise any of your previous certs; not necessarily an easy feat but still a new vector
  - mehrdadn 6y ago
    No it doesn't? All that happens is the previous cert would be accepted with a milder warning for a few weeks (not permanently) after you get a new one. It's just a small grace window to let users still be able to use the site. Just like an expiration date on your milk. There's no need to toss it out immediately just because an extra nanosecond passed.
    - lilyball 6y ago
      This would require everyone to understand that previous certs still require high-security for at least a few weeks post expiration. This is not something we can rely on people understanding.
      - im3w1l 6y ago
        Allowing bypass is the old way of doing things, and many non-browsers still allow it, so you should ideally hold on to old certs indefinitely, but at least for a short while.
      - deleted 6y ago
        [deleted]
webnanners 6y ago
This happened to braintree/paypal like a month ago.. and broke their API
- jcims 6y ago
  Happens to all sorts of folks - https://venturebeat.com/2015/04/04/gmails-ssl-certificate-for-smtp-appears-to-have-expired/ https://venturebeat.com/2015/04/04/gmails-ssl-certificate-fo...
deleted 6y ago
[deleted]
x87678r 6y ago
Like many I've been burnt by this problem. I have a rule now where no certificate should ever be within 6 months of expiry, ideally we should renew every month.
prepend 6y ago
I hate getting in arguments with a few sysadmins and certificate salespeople how long certificate periods are perfectly safe. I’d rather have 5 year certs and rely more on revocation than have this stupid exercise where people must renew every year or 13 months that just so happens to collect tons of rent seeking income from a few firms. It’s kind of like how the shift to non-expiring passwords. We were trying to correct for the risk of a compromised password by making it harder to have secure passwords. I think we’re better off with having really strong passwords that only ever get changed when necessary and allowing this my monitoring login actions for weird stuff.
- NobodyNada 6y ago
  > people must renew every year or 13 months that just so happens to collect tons of rent seeking income from a few firms Isn’t it primarily free CAs like LE that are pushing for shorter expiration times? IIRC the primary argument is not about security or safety, but rather that shorter certificate lifetimes encourage companies to automate certificate renewal/make it a regular part of their business routine. If you only have to renew a certificate every five years, then it’s really easy to forget.
  - prepend 6y ago
    I think it’s just as easy to automate a monthly renewal as a five year renewal. The argument that gets presented to me is that shorter times reduce the risk of someone compromising the cert and pretending to be the real server. But that risk requires a pretty motivated attacker to also compromise DNS or server farm and that probably doesn’t matter because they will plan around any renewal cycle.
    - jasonpeacock 6y ago
      When you tell management "we need to automate this process that won't happen for 5 years", you're not going to get approval. When you tell management "we need to automate this process that will happen every month", you will get approval. It's not about the effort to automate the process, it's the opportunity cost of investing that effort.
spullara 6y ago
Why don't systems that use certificates have a configurable webhook they call to warn of such things?
jijji 6y ago
echo "certbot-auto renew --nginx" > /etc/cron.weekly/renew_certs.sh
szc 6y ago
I personally think that TLS certificate expiry should be a server problem not a client problem. The TLS server code is the piece that is using the certificate every time a page is requested. Why doesn't server code log an error warning that the certificate is going to expire? Why doesn't the server just stop serving connections when the cert has expired? Stopping connections ought to get the attention of the service owner rather than force clients to use out-of-band mechanisms to reach the service owner. Alternatively perhaps imminent expiry should be a trigger for renewal or some other alerting mechanism. Is there a callback like this in current TLS API stacks that could be used to make this work? (I'm not super familiar with TLS server side APIs, I know there are client callbacks for certificate validation). It would probably be wise to do the check carefully so as to not consume too many resources. A well thought out mechanism could trigger an external process for notification or even automatic renewal - even when needing to cross a privilege boundary, perhaps touching a file or an IPC message. I think this would be slightly better than some of the current setups for things like Let's Encrypt that end up running many times unnecessarily. Would be a much better fit for resource constrained embedded devices. [edited: added back a sentence I inadvertently removed]

74 points by k_sze 6y ago

dildozer 6y ago

It is a different Krebs, but still ironic

dboreham 6y ago
Other way around no, the Krebs in the news is the different Krebs?
- dildozer 6y ago
  Yes Chris Krebs was fired, Brian Krebs is krebsonsecurity, no relation

dboreham 6y ago

Assume this is deliberate, since real domain hijackers would use a valid cert. Also helps to ensure browser vendors don't disable cert validity bypass. Very clever.

lozaning 6y ago
Based on his tweet it sure seems like he forgot to renew, and this isn't some kind of genius move to keep anyone honest. https://twitter.com/briankrebs/status/1328863446105010177 https://twitter.com/briankrebs/status/1328863446105010177
- panarky 6y ago
  That tweet says "Despite what the browsers may be saying, the site is still safe to visit." Is it though? Asking people to ignore browser warnings seems like bad advice from a security expert.
  - k_sze 6y ago
    Yeah, I, too, found that to be a really odd piece of advice from a security expert. If I were the Brian (but I'm not), I would have asked followers to not trust the site until the certificate issue is fixed, even though I "know" my site is still safe. I think the properly cautious attitude is to consider all bets being off when a certificate is invalid for whatever reason. There is no guarantee what your visitors are actually getting.
    - marta_morena_28 6y ago
      Bias finds its way into every corner. And no, it's not safe unless you do some extensive analysis of the certificate in question. Is this actually a valid/genuine certificate, besides the timestamp? A normal user will have a hard time verifying that.
  - Mathnerd314 6y ago
    It's safe considering the threat model: the worst his site has seen is some DDOS attacks. With a MITM his site might end up hosting a 0-day, but hijacking is unlikely to begin with due to how low-profile his site is (outside of tech circles). And they'd have to attack DNS as well as his certificate.

tvbuzz 6y ago

Fake news designed to cut down on DDOS

ludditetech 6y ago

Chuckle, happens to the best of us - obviously.

k_sze 6y ago
I'm surprised that Brian Krebs still uses Comodo. Why not LetsEncrypt with automated renewal?
- mpd 6y ago
  While you're not paying for the cert, there is certainly still a cost involved.
  - nkozyra 6y ago
    I would say the technical hurdle is about equal to comodo. What other cost is there?
    - mpd 6y ago
      Comodo is a renewal and updating an artifact (i.e. the actual cert), then you're done, vs. having to handle LE's API to deal with doing it 'automatically' and then carrying that forward. My point is simply that the cost is not zero.
      - lights0123 6y ago
        You can still just replace the cert manually like you would any other CA. It's just there's no official GUI to do it with LE and you have to do it more often.
      - jasonpeacock 6y ago
        There's already mature, widely adopted tools like certbot and acme.sh that do this automatically for you. It may not be zero, but it's no more than Comodo.
  - corytheboyd 6y ago

mehrdadn 6y ago

I never understood why browsers don't just go ahead and load websites with expired certificates and merely provide milder warnings for a few weeks/months. The expiration date doesn't mark any meaningful real-world event that indicates the private key might be compromised... it's just an expiration date. Why set off all the alarms and make the user freak out and make it so hard to visit the site as soon as the certificate becomes 1 millisecond too old? It seems to violate common sense.

whoisjohnkid 6y ago
That would open a new vector of attack where an attacker would simply have to compromise any of your previous certs; not necessarily an easy feat but still a new vector
- mehrdadn 6y ago
  No it doesn't? All that happens is the previous cert would be accepted with a milder warning for a few weeks (not permanently) after you get a new one. It's just a small grace window to let users still be able to use the site. Just like an expiration date on your milk. There's no need to toss it out immediately just because an extra nanosecond passed.
  - lilyball 6y ago
    This would require everyone to understand that previous certs still require high-security for at least a few weeks post expiration. This is not something we can rely on people understanding.
    - im3w1l 6y ago
      Allowing bypass is the old way of doing things, and many non-browsers still allow it, so you should ideally hold on to old certs indefinitely, but at least for a short while.
    - deleted 6y ago
      [deleted]

webnanners 6y ago

This happened to braintree/paypal like a month ago.. and broke their API

jcims 6y ago
Happens to all sorts of folks - https://venturebeat.com/2015/04/04/gmails-ssl-certificate-for-smtp-appears-to-have-expired/ https://venturebeat.com/2015/04/04/gmails-ssl-certificate-fo...

deleted 6y ago

[deleted]

x87678r 6y ago

Like many I've been burnt by this problem. I have a rule now where no certificate should ever be within 6 months of expiry, ideally we should renew every month.

prepend 6y ago

I hate getting in arguments with a few sysadmins and certificate salespeople how long certificate periods are perfectly safe. I’d rather have 5 year certs and rely more on revocation than have this stupid exercise where people must renew every year or 13 months that just so happens to collect tons of rent seeking income from a few firms. It’s kind of like how the shift to non-expiring passwords. We were trying to correct for the risk of a compromised password by making it harder to have secure passwords. I think we’re better off with having really strong passwords that only ever get changed when necessary and allowing this my monitoring login actions for weird stuff.

NobodyNada 6y ago
> people must renew every year or 13 months that just so happens to collect tons of rent seeking income from a few firms Isn’t it primarily free CAs like LE that are pushing for shorter expiration times? IIRC the primary argument is not about security or safety, but rather that shorter certificate lifetimes encourage companies to automate certificate renewal/make it a regular part of their business routine. If you only have to renew a certificate every five years, then it’s really easy to forget.
- prepend 6y ago
  I think it’s just as easy to automate a monthly renewal as a five year renewal. The argument that gets presented to me is that shorter times reduce the risk of someone compromising the cert and pretending to be the real server. But that risk requires a pretty motivated attacker to also compromise DNS or server farm and that probably doesn’t matter because they will plan around any renewal cycle.
  - jasonpeacock 6y ago
    When you tell management "we need to automate this process that won't happen for 5 years", you're not going to get approval. When you tell management "we need to automate this process that will happen every month", you will get approval. It's not about the effort to automate the process, it's the opportunity cost of investing that effort.

spullara 6y ago

Why don't systems that use certificates have a configurable webhook they call to warn of such things?

jijji 6y ago

echo "certbot-auto renew --nginx" > /etc/cron.weekly/renew_certs.sh

szc 6y ago

I personally think that TLS certificate expiry should be a server problem not a client problem. The TLS server code is the piece that is using the certificate every time a page is requested. Why doesn't server code log an error warning that the certificate is going to expire? Why doesn't the server just stop serving connections when the cert has expired? Stopping connections ought to get the attention of the service owner rather than force clients to use out-of-band mechanisms to reach the service owner. Alternatively perhaps imminent expiry should be a trigger for renewal or some other alerting mechanism. Is there a callback like this in current TLS API stacks that could be used to make this work? (I'm not super familiar with TLS server side APIs, I know there are client callbacks for certificate validation). It would probably be wise to do the check carefully so as to not consume too many resources. A well thought out mechanism could trigger an external process for notification or even automatic renewal - even when needing to cross a privilege boundary, perhaps touching a file or an IPC message. I think this would be slightly better than some of the current setups for things like Let's Encrypt that end up running many times unnecessarily. Would be a much better fit for resource constrained embedded devices. [edited: added back a sentence I inadvertently removed]