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This is especially funny to me as our PCI DSS Network Scan just started flagging not having a HPKP Header as something thats necessary to remediate. I've had to

This is especially funny to me as our PCI DSS Network Scan just started flagging not having a HPKP Header as something thats necessary to remediate. I've had to waste half a day on the phone and then to write a Risk Mitigation Plan that explains how we mitigate the risk of an MITM Attack in case our CA gets breached...

geofft 9y ago
... isn't the risk that HPKP mitigates the risk of a MITM attack in case some other CA gets breached?
- detaro 9y ago
  HPKP also protects against your CA if you pin the direct private keys your servers use, but I bet it also is quite annoying to come up with a good plan for how you are not going to loose/delete all the private keys you have pinned...
  - geofft 9y ago
    Right. I'm curious which approach the auditors wanted - either one would be a weird thing to mandate! In theory, pinning your servers' private keys is actually kind of reasonable, if you generate like two or three sets of backup private keys and put them in off-site storage. And I've long been an advocate of buying at least one backup certificate from another CA just in case your current one gets distrusted. (And it makes sense from a technical perspective why HPKP supports both of these approaches, but the ambiguity probably didn't help it from a policy perspective).
deleted 9y ago
[deleted]
tptacek 9y ago
It is deeply fucked up if a scanning checklist demands PKP, since most sites --- including most commerce sites --- shouldn't pin.
- deleted 9y ago
  [deleted]
- user5994461 9y ago
  Well, try explaining that to the HSTS and HPKP folks. They already have answers littered on stack overflow and HN to advise to enable it for anything and everything. With exactly zero consideration for the potential to backfire. It's only a matter of time before an intern or an audit guy have it deployed on majorcompany.com and result in a disaster. Symptom includes none of the client ever able to access the site again.
  - lucaspiller 9y ago
    Last year I was contracting at an NGO where somebody decided to add our domain to an HSTS preload list. This worked great for the public facing site, which was already served over HTTPS, but we also had a load of internal apps on the same domain. They were only accessible from our network (ethernet or VPN), so we hadn’t bothered with HTTPS before. Oh and we only found out about the issue when Chrome updated and everything broke - it was a fun few days!
  - Buge 9y ago
    HSTS should never result in "none of the client ever able to access the site again".
    - lmm 9y ago
      HPKP can, if you pin a key and then lose the key you pinned.
      - Buge 9y ago
        I know. But you shouldn't lump the dangerousness of HPKP on HSTS. Also with HPKP you shouldn't just pin one key. You should pin several keys you own as well as several root and intermediate keys. But I agree it's very difficult to do right and there's still a risk of it failing.
  - 9y ago
abarringer 9y ago
Are you using Qualys? It seems they are having major issues with header checks starting around Oct 1st. Tenable however still passes sites without HPKP. Getting our vendors, like fortinet, to implement all the security headers Qualys now demands will be impossible so we are checking other ASV's to see how they respond to our sites. Just for jollies you should go check pci.qualys.com's security headers.
eganist 9y ago
https://twitter.com/eganist/status/920399513638133761 https://twitter.com/eganist/status/920399513638133761 Glad there are more reports of this showing up.

geofft 9y ago

... isn't the risk that HPKP mitigates the risk of a MITM attack in case some other CA gets breached?

detaro 9y ago
HPKP also protects against your CA if you pin the direct private keys your servers use, but I bet it also is quite annoying to come up with a good plan for how you are not going to loose/delete all the private keys you have pinned...
- geofft 9y ago
  Right. I'm curious which approach the auditors wanted - either one would be a weird thing to mandate! In theory, pinning your servers' private keys is actually kind of reasonable, if you generate like two or three sets of backup private keys and put them in off-site storage. And I've long been an advocate of buying at least one backup certificate from another CA just in case your current one gets distrusted. (And it makes sense from a technical perspective why HPKP supports both of these approaches, but the ambiguity probably didn't help it from a policy perspective).

deleted 9y ago

[deleted]

tptacek 9y ago

It is deeply fucked up if a scanning checklist demands PKP, since most sites --- including most commerce sites --- shouldn't pin.

deleted 9y ago
[deleted]
user5994461 9y ago
Well, try explaining that to the HSTS and HPKP folks. They already have answers littered on stack overflow and HN to advise to enable it for anything and everything. With exactly zero consideration for the potential to backfire. It's only a matter of time before an intern or an audit guy have it deployed on majorcompany.com and result in a disaster. Symptom includes none of the client ever able to access the site again.
- lucaspiller 9y ago
  Last year I was contracting at an NGO where somebody decided to add our domain to an HSTS preload list. This worked great for the public facing site, which was already served over HTTPS, but we also had a load of internal apps on the same domain. They were only accessible from our network (ethernet or VPN), so we hadn’t bothered with HTTPS before. Oh and we only found out about the issue when Chrome updated and everything broke - it was a fun few days!
- Buge 9y ago
  HSTS should never result in "none of the client ever able to access the site again".
  - lmm 9y ago
    HPKP can, if you pin a key and then lose the key you pinned.
    - Buge 9y ago
      I know. But you shouldn't lump the dangerousness of HPKP on HSTS. Also with HPKP you shouldn't just pin one key. You should pin several keys you own as well as several root and intermediate keys. But I agree it's very difficult to do right and there's still a risk of it failing.
- 9y ago

abarringer 9y ago

Are you using Qualys? It seems they are having major issues with header checks starting around Oct 1st. Tenable however still passes sites without HPKP. Getting our vendors, like fortinet, to implement all the security headers Qualys now demands will be impossible so we are checking other ASV's to see how they respond to our sites. Just for jollies you should go check pci.qualys.com's security headers.

eganist 9y ago

https://twitter.com/eganist/status/920399513638133761 https://twitter.com/eganist/status/920399513638133761 Glad there are more reports of this showing up.