6 ms·

IIUC, if Slack had done the correct thing, only wildcard DNS records (if any) would have been affected. They would certainly not have had a complete DNS blacko

by teddyh 1y ago

IIUC, if Slack had done the correct thing, only wildcard DNS records (if any) would have been affected. They would certainly not have had a complete DNS blackout. I would classify that as significant. > The story for implementers is just as bad - the specifications are baroque, filled with lousy crypto and poorly thought-out options. I don’t care. So is almost every other standard, but until something better comes along, DNSSEC is what we have. Arguing that a working and implemented solution should not be used since it is worse than a non-existing theoretical perfect solution is both: 1. True 2. Completely and utterly useless, except as a way to waste everyone’s time and drain their energy.

marcusb 1y ago
> IIUC, if Slack had done the correct thing, only wildcard DNS records (if any) would have been affected There's the problem - you DON'T understand. Straight from the post-portem that you clearly have not read: One microsecond later, app.slack.com fails to resolve with a ‘ERR_NAME_NOT_RESOLVED’ error: [screenshot of error ] This indicated there was likely a problem with the ‘*.slack.com’ wildcard record since we didn’t have a wildcard record in any of the other domains where we had rolled out DNSSEC on. Yes, it was an oversight that we did not test a domain with a wildcard record before attempting slack.com — learn from our mistakes! > I don’t care. So is almost every other standard, Cool story. I do care. I'd like to see greater protection of the DNS infrastructure. DNSSEC adoption is hovering around 4%. TLS for HTTP is around 90%. At least part of that discrepancy is due to how broken DNSSEC is.
- teddyh 1y ago
  They could have done a quick fix by adding an explicit app.slack.com record. But instead they removed the DNSSEC signing from the whole domain, thereby invalidating all records, not just the wildcard ones. > I do care. I will care once something else comes around with any promise of being implemented and rolled out. Until then, I see no need to discourage the adoption of DNSSEC, or disparage its design, except when designing its newer version or replacement. > I'd like to see greater protection of the DNS infrastructure. DNSSEC adoption is hovering around 4%. I work at a registrar and DNS hosting provider for more than 10.000 domains. More than 70% of them have DNSSEC.
  - marcusb 1y ago
    > They could have done a quick fix by adding an explicit app.slack.com record. But instead they removed the DNSSEC signing from the whole domain, thereby invalidating all records, not just the wildcard ones. 1) That would do nothing to fix resolvers that had already cached NSEC responses lacking type maps. 2) That presumes the wildcard record was superfluous and could have been replaced with a simple A record for a single or small number of records. Would love to see a citation supporting that. 3) That presumes the Slack team could have quickly identified that the problem they were having was caused by the fact that app.slack.com (and whatever other hosts resolve from that wildcard) was caused by the fact the record was configured as a wildcard and would have been resolved by eliminating the wildcard record. If you read the postmortem, it is clear they zeroed in on the wildcard record as being suspect, but had to work with AWS to figure out the exact cause. I doubt that was an instantaneous process. Any way you slice it, there was no quick way to fully recover from this bug once they hit it, and my argument is that the design of DNSSEC makes these issues a) likely to happen and b) difficult to model ahead of time, while providing fairly marginal security benefit. At this point, I really don't care if you agree or disagree. > I will care once something else comes around with any promise of being implemented and rolled out. Yeah. DNSSEC is going to be widely deployed any day now. The year after the year of Linux on the desktop. > I work at a registrar and DNS hosting provider for more than 10.000 domains. More than 70% of them have DNSSEC. Cool. There are, what, 750 million domains registered worldwide? We are at nowhere near 10% adoption worldwide, let alone 70%. Of the top 100 domains -- the operators you would assume would be the most concerned about DNS response poisoning -- *six* have turned DNSSEC on.
    - tptacek 1y ago
      Of the top 100, only 2 have DNSSEC enabled --- cloudflare.com and cloudflare.net.
      - marcusb 1y ago
        I imagine it depends on which "top domain" list you use. I use Cloudflare radar. As of today, for their top 100 domains, 6 have published DS records: 2371 13 2 32996839A6D808AFE3EB4A795A0E6A7A39A76FC52FF228B22B76F6D6 3826F2B9 cloudflare.com 2371 13 2 F52DBA4AAEA13A1F457C0FB4C1953F40E16AFC5C5E79EDF7CEED0FCF 0CBD81F0 cloudflare-dns.com 53074 13 2 86F2929EE3E5E501032B6DC94841A4A056A2D2876CABCF46A5F8907E B4917782 one.one 56044 8 2 1B0A7E90AA6B1AC65AA5B573EFC44ABF6CB2559444251B997103D2E4 0C351B08 dns.google 48553 13 2 57AF2F182A541A91AD24CC6583867C2BA331255B03E2A32579A625AD 1F3BE3CA taboola.com 33751 8 2 90C6CD28626CA7B8E3A1FACAD58D20D486E52DF040B9B2F085ACD5C7 03E624C6 nist.gov Not that it matters much one way or the other - you won't find a top 100 domains list where, say, 50 have DNSSEC enabled.
growse 1y ago
> So is almost every other standard, but until something better comes along, DNSSEC is what we have. I must have missed the last 40 years of the internet where DNS without DNSSEC has worked (and continues to work) just fine.

by teddyh 1y ago

marcusb 1y ago

> IIUC, if Slack had done the correct thing, only wildcard DNS records (if any) would have been affected There's the problem - you DON'T understand. Straight from the post-portem that you clearly have not read: One microsecond later, app.slack.com fails to resolve with a ‘ERR_NAME_NOT_RESOLVED’ error: [screenshot of error ] This indicated there was likely a problem with the ‘*.slack.com’ wildcard record since we didn’t have a wildcard record in any of the other domains where we had rolled out DNSSEC on. Yes, it was an oversight that we did not test a domain with a wildcard record before attempting slack.com — learn from our mistakes! > I don’t care. So is almost every other standard, Cool story. I do care. I'd like to see greater protection of the DNS infrastructure. DNSSEC adoption is hovering around 4%. TLS for HTTP is around 90%. At least part of that discrepancy is due to how broken DNSSEC is.

teddyh 1y ago
They could have done a quick fix by adding an explicit app.slack.com record. But instead they removed the DNSSEC signing from the whole domain, thereby invalidating all records, not just the wildcard ones. > I do care. I will care once something else comes around with any promise of being implemented and rolled out. Until then, I see no need to discourage the adoption of DNSSEC, or disparage its design, except when designing its newer version or replacement. > I'd like to see greater protection of the DNS infrastructure. DNSSEC adoption is hovering around 4%. I work at a registrar and DNS hosting provider for more than 10.000 domains. More than 70% of them have DNSSEC.
- marcusb 1y ago
  > They could have done a quick fix by adding an explicit app.slack.com record. But instead they removed the DNSSEC signing from the whole domain, thereby invalidating all records, not just the wildcard ones. 1) That would do nothing to fix resolvers that had already cached NSEC responses lacking type maps. 2) That presumes the wildcard record was superfluous and could have been replaced with a simple A record for a single or small number of records. Would love to see a citation supporting that. 3) That presumes the Slack team could have quickly identified that the problem they were having was caused by the fact that app.slack.com (and whatever other hosts resolve from that wildcard) was caused by the fact the record was configured as a wildcard and would have been resolved by eliminating the wildcard record. If you read the postmortem, it is clear they zeroed in on the wildcard record as being suspect, but had to work with AWS to figure out the exact cause. I doubt that was an instantaneous process. Any way you slice it, there was no quick way to fully recover from this bug once they hit it, and my argument is that the design of DNSSEC makes these issues a) likely to happen and b) difficult to model ahead of time, while providing fairly marginal security benefit. At this point, I really don't care if you agree or disagree. > I will care once something else comes around with any promise of being implemented and rolled out. Yeah. DNSSEC is going to be widely deployed any day now. The year after the year of Linux on the desktop. > I work at a registrar and DNS hosting provider for more than 10.000 domains. More than 70% of them have DNSSEC. Cool. There are, what, 750 million domains registered worldwide? We are at nowhere near 10% adoption worldwide, let alone 70%. Of the top 100 domains -- the operators you would assume would be the most concerned about DNS response poisoning -- *six* have turned DNSSEC on.
  - tptacek 1y ago
    Of the top 100, only 2 have DNSSEC enabled --- cloudflare.com and cloudflare.net.
    - marcusb 1y ago
      I imagine it depends on which "top domain" list you use. I use Cloudflare radar. As of today, for their top 100 domains, 6 have published DS records: 2371 13 2 32996839A6D808AFE3EB4A795A0E6A7A39A76FC52FF228B22B76F6D6 3826F2B9 cloudflare.com 2371 13 2 F52DBA4AAEA13A1F457C0FB4C1953F40E16AFC5C5E79EDF7CEED0FCF 0CBD81F0 cloudflare-dns.com 53074 13 2 86F2929EE3E5E501032B6DC94841A4A056A2D2876CABCF46A5F8907E B4917782 one.one 56044 8 2 1B0A7E90AA6B1AC65AA5B573EFC44ABF6CB2559444251B997103D2E4 0C351B08 dns.google 48553 13 2 57AF2F182A541A91AD24CC6583867C2BA331255B03E2A32579A625AD 1F3BE3CA taboola.com 33751 8 2 90C6CD28626CA7B8E3A1FACAD58D20D486E52DF040B9B2F085ACD5C7 03E624C6 nist.gov Not that it matters much one way or the other - you won't find a top 100 domains list where, say, 50 have DNSSEC enabled.

growse 1y ago

> So is almost every other standard, but until something better comes along, DNSSEC is what we have. I must have missed the last 40 years of the internet where DNS without DNSSEC has worked (and continues to work) just fine.