Here is a proposed DRAFT of a CA Communication that I would like to send soon. I will greatly appreciate your constructive feedback.
Note that the “<date TBD>” is proposed because any such customers are probably very large enterprise customers who likely will have to bring up a corporate certificate infrastructure and deploy a new root to tens of thousands of heterogeneous devices, and their corporate network may include WiFi access points, and therefore also mobile devices. I am thinking that the date should be something between 2 and 3 months after the official communication is sent.
==
Subject: Mozilla Communication: Action requested by <date 2 weeks out>
Dear Certification Authority,
This note requests a set of immediate actions on your behalf, as a participant in the Mozilla root program.
Please reply by <date 2 weeks out> to confirm completion of the following actions or state when these actions will be completed.
1) Subordinate CAs chaining to CAs in Mozilla’s root program may not be used for MITM purposes, regardless of whether it is in a closed and controlled environment or not. Please review all of your subordinate CAs to make sure that they may not be used for MITM purposes. Any existing subordinate CAs that may be used for that purpose must be revoked and any corresponding HSMs destroyed by <date TBD>. For each subordinate CA that is revoked, send me:
a) The certificate that signed the subCA. If it is a root certificate in NSS, then the root certificate's subject and SHA1 fingerprint.
b) The Serial Number of the revoked certificate.
c) The CRL that contains the serial number of the revoked certificate.
As a CA in Mozilla’s root program you are ultimately responsible for certificates issued by you and your subordinate CAs. After <date TBD> if it is found that a subordinate CA is being used for MITM, we will remove the corresponding root certificate. Based on Mozilla’s assessment, we may also remove any of your other root certificates, and root certificates from other organizations that cross-sign your certificates.
2) Please add a statement to your CP/CPS committing that you will not issue a subordinate certificate that may be used for MITM or traffic management of domain names or IPs that the party does not legitimately own or control. Send me the URL to the updated document(s) and the impacted sections or page numbers.
3) It has come to our attention that there may still be EV SSL certificates that do not comply with all of the requirements of the EV guidelines. Please review all of your EV SSL certificates and revoke any that do not meet the EV requirements. This includes, but is not limited to maximum validity period of the certificate, subject naming, minimum key sizes, required extensions, and maximum expiration time of OCSP responses.
4) Certificates chaining to root certificates in Mozilla’s root program should not have 512-bit keys or MD5 algorithms. Please scan the certificates chaining to your root certificates in NSS, and revoke any certificates that contain small key sizes or MD5 algorithms.
5) The CA/Browser Forum has released the "Baseline Requirements for the Issuance and Management of Publicly Trusted Certificates,” which is available here: http://www.cabforum.org/. Discussions are in progress in the mozilla.dev.security.policy forum to update Mozilla’s CA Certificate Policy to require that CAs meet these baseline requirements for issuance of SSL/TLS certificates. Please contribute to the discussions in the mozilla.dev.security.policy forum, and update your operations and documentation as needed to meet the baseline requirements by the effective date of July 1, 2012.
Participation in Mozilla's root program is at our sole discretion, and we will take whatever steps are necessary to keep our users safe. Nevertheless, we believe that the best approach to safeguard that security is to work with CAs as partners, to foster open and frank communication, and to be diligent in looking for ways to improve. Thank you for your participation in this pursuit.
Regards,
Kathleen Wilson
Module Owner of Mozilla's CA Certificates Module
> 2) Please add a statement to your CP/CPS committing that you will not > issue a subordinate certificate that may be used for MITM or traffic > management of domain names or IPs that the party does not legitimately > own or control. Send me the URL to the updated document(s) and the > impacted sections or page numbers.
I think this requirement is wrong in that if a CPS doesn't have a stipulation for that, the CA supposedly isn't doing it. E.g. The CA must have a clear policy under which circumstances a certificate may be issued, which incidentally should be compliant to the Mozilla CA Policy. (For example the StartCom CA Policy has clear disclosure about the validation requirements and it's almost an insult to me to have such a statement as the above included in the policy - as if there was ever a policy that could have allowed that or would even be considered).
Rather, I suggest to require FULL public disclosure of all CP/CPS within the responsibility of any CA root and if any of them has a stipulation other than the Mozilla CA Policy, to eliminate them within XXX time. Should Mozilla or any other party (Google's Chrome certificate pinning) find such certificates, Mozilla would be forced to act accordingly.
> 3) It has come to our attention that there may still be EV SSL > certificates that do not comply with all of the requirements of the EV > guidelines. Please review all of your EV SSL certificates and revoke > any that do not meet the EV requirements. This includes, but is not > limited to maximum validity period of the certificate, subject naming, > minimum key sizes, required extensions, and maximum expiration time of > OCSP responses.
I'm not sure if this issue should be dealt with separately, it appears to drown between all the rest. Also if you know about such certificates, you should draw the attention of that CA and maybe also open a bug for each of them.
> 4) Certificates chaining to root certificates in Mozilla’s root > program should not have 512-bit keys or MD5 algorithms.
Didn't you meant to say 1024bit? Shouldn't the required minimum supposed to be 2048 bit these days?
> 5) The CA/Browser Forum has released the "Baseline Requirements for > the Issuance and Management of Publicly Trusted Certificates,” which > is available here: http://www.cabforum.org/. Discussions are in > progress in the mozilla.dev.security.policy forum to update Mozilla’s > CA Certificate Policy to require that CAs meet these baseline > requirements for issuance of SSL/TLS certificates. Please contribute > to the discussions in the mozilla.dev.security.policy forum, and > update your operations and documentation as needed to meet the > baseline requirements by the effective date of July 1, 2012.
Again, don't mix apples with oranges. I suggest to invite the community not within such a publication (a serious issue in itself).
> Here is a proposed DRAFT of a CA Communication that I would like to send > soon. I will greatly appreciate your constructive feedback.
> Note that the “<date TBD>” is proposed because any such customers are > probably very large enterprise customers who likely will have to bring > up a corporate certificate infrastructure and deploy a new root to tens > of thousands of heterogeneous devices, and their corporate network may > include WiFi access points, and therefore also mobile devices. I am > thinking that the date should be something between 2 and 3 months after > the official communication is sent.
> ==
> Subject: Mozilla Communication: Action requested by <date 2 weeks out>
> Dear Certification Authority,
> This note requests a set of immediate actions on your behalf, as a > participant in the Mozilla root program.
> Please reply by <date 2 weeks out> to confirm completion of the > following actions or state when these actions will be completed.
> 1) Subordinate CAs chaining to CAs in Mozilla’s root program may not be > used for MITM purposes, regardless of whether it is in a closed and > controlled environment or not. Please review all of your subordinate CAs > to make sure that they may not be used for MITM purposes. Any existing > subordinate CAs that may be used for that purpose must be revoked and > any corresponding HSMs destroyed by <date TBD>. For each subordinate CA > that is revoked, send me:
> a) The certificate that signed the subCA. If it is a root certificate in > NSS, then the root certificate's subject and SHA1 fingerprint.
> b) The Serial Number of the revoked certificate.
> c) The CRL that contains the serial number of the revoked certificate.
> As a CA in Mozilla’s root program you are ultimately responsible for > certificates issued by you and your subordinate CAs. After <date TBD> if > it is found that a subordinate CA is being used for MITM, we will remove > the corresponding root certificate. Based on Mozilla’s assessment, we > may also remove any of your other root certificates, and root > certificates from other organizations that cross-sign your certificates.
> 2) Please add a statement to your CP/CPS committing that you will not > issue a subordinate certificate that may be used for MITM or traffic > management of domain names or IPs that the party does not legitimately > own or control. Send me the URL to the updated document(s) and the > impacted sections or page numbers.
> 3) It has come to our attention that there may still be EV SSL > certificates that do not comply with all of the requirements of the EV > guidelines. Please review all of your EV SSL certificates and revoke any > that do not meet the EV requirements. This includes, but is not limited > to maximum validity period of the certificate, subject naming, minimum > key sizes, required extensions, and maximum expiration time of OCSP > responses.
> 4) Certificates chaining to root certificates in Mozilla’s root program > should not have 512-bit keys or MD5 algorithms. Please scan the > certificates chaining to your root certificates in NSS, and revoke any > certificates that contain small key sizes or MD5 algorithms.
> 5) The CA/Browser Forum has released the "Baseline Requirements for the > Issuance and Management of Publicly Trusted Certificates,” which is > available here: http://www.cabforum.org/. Discussions are in progress in > the mozilla.dev.security.policy forum to update Mozilla’s CA Certificate > Policy to require that CAs meet these baseline requirements for issuance > of SSL/TLS certificates. Please contribute to the discussions in the > mozilla.dev.security.policy forum, and update your operations and > documentation as needed to meet the baseline requirements by the > effective date of July 1, 2012.
> Participation in Mozilla's root program is at our sole discretion, and > we will take whatever steps are necessary to keep our users safe. > Nevertheless, we believe that the best approach to safeguard that > security is to work with CAs as partners, to foster open and frank > communication, and to be diligent in looking for ways to improve. Thank > you for your participation in this pursuit.
> Regards,
> Kathleen Wilson
> Module Owner of Mozilla's CA Certificates Module
> ===
In #5, after the sentence
> Discussions are in progress in > the mozilla.dev.security.policy forum to update Mozilla’s CA Certificate > Policy to require that CAs meet these baseline requirements for issuance > of SSL/TLS certificates.
insert the additional sentence: "Mozilla reserves the right to impose in
its policy revision requirements beyond those Baseline Requirements."
After all, the CA/Browser Forum established BASELINE (i.e., minimal)
requirements, not maximal requirements.
> Here is a proposed DRAFT of a CA Communication that I would like to
> send soon. I will greatly appreciate your constructive feedback.
Thank you!
> Note that the “<date TBD>” is proposed because any such customers
> are probably very large enterprise customers who likely will have to
> bring up a corporate certificate infrastructure and deploy a new root
> to tens of thousands of heterogeneous devices, and their corporate
> network may include WiFi access points, and therefore also mobile
> devices.
Everyone with any common sense had to know that such certificates are
not acceptable, and they should never have been issued. Not just the CAs
- system administrators who use such a model know very well that what
they are doing is nothing else than a MitM attack.
Allowing months to pass just to protect those that blatantly violate
policies and their customers who perform MitM attacks seems just wrong.
Unless someone actually uses the same CA for attacking SSL and
protecting their own network:
a) They do not need to roll this out immediately, they just need to
stop doing MitM attacks until they managed to roll it out
b) They only need to roll out to clients to be MitM-ed, i.e. not all
WiFi APs etc.
I do not see any reason why knowingly allowing MitM attacks would be a
good idea. Therefore, I think the date for the revocation should still
be 2 weeks at most.
> b) The Serial Number of the revoked certificate.
I would suggest the full certificate including information about who it
was issued to. In my opinion, this needs to be disclosed to the
potentially affected audience, i.e. users of Mozilla products, i.e. the
public. I am sure that, with sufficient motivation, the CAs will find a
way to make this possible. We wouldn't accept "a contract prevents us
from revoking the MitM CA" for an answer, either. I would consider it OK
to allow for some additional time for this, as this is where possibly
multiple legal departments may need to work together. This is why I
suggested (and still suggest) 1 month from the announcement for disclosure.
Kind regards,
Jan
-- Please avoid sending mails, use the group instead.
If you really need to send me an e-mail, mention "FROM NG"
in the subject line, otherwise my spam filter will delete your mail.
Sorry for the inconvenience, thank the spammers...
> Rather, I suggest to require FULL public disclosure of all CP/CPS > within the responsibility of any CA root and if any of them has a > stipulation other than the Mozilla CA Policy, to eliminate them within > XXX time. Should Mozilla or any other party (Google's Chrome > certificate pinning) find such certificates, Mozilla would be forced > to act accordingly.
I was thinking about this some more and for various reasons I don't think that this communication is either going to contribute much nor is it really necessary.
Look, Mozilla has a policy, there is no reason to require something that doesn't comply to the policy anyway. The policy hasn't changed and I'd advise Mozilla to apply its own policy, simply as that.
When we were working on the baselines requirements, clear guidelines have been defined under which circumstances server certificates can be issued. The Mozilla CA Policy has also a clear definition for a while now. The EV guidelines also have clear requirements set forth...
So what exactly do you want say? That CAs must comply to the policies or else? Isn't this just a bit too little too late or simply not relevant for the majority of CAs anyway? Wouldn't it be much better to apply your policy now to the letter? Don't you know what your policy says and how to enforce it?
I'm also concerned that yet another communication from Mozilla will result in an inflation of such messages, eventually they'll not have the desired effect. In the proposed communication there is nothing new, nothing that wasn't require before. Instead what I however would propose is:
A) Require from now on disclosure of ALL policies and practices
statements that are related to a particular root
B) Disclosure of ALL CA certificates (sub or cross-signed) to a
particular root
at every new inclusion request and for every submitted yearly audit statement that Mozilla requires to be submitted by the CAs. Within less than a year, Mozilla should have all policies and CA certificates that are chained to a root included in Mozilla software disclosed.
As to particular incidents, unexpected disclosures, non-compliance to the various policies (Mozilla, Baselines, EV), Mozilla should have a policy in place about what to do. Is your policy is to send out a communication every time some CA doesn't comply to the requirements set forth....?
> Note that the “<date TBD>” is proposed because any such customers are > probably very large enterprise customers who likely will have to bring > up a corporate certificate infrastructure [... ]I am > thinking that the date should be something between 2 and 3 months after > the official communication is sent.
While I would also prefer a much shorter time frame: what about at least a compromise if that is not possible? Require them to report the SHA1 fingerprint, subject, serial number within 2 weeks and publish the checksum somewhere. Then users could use an add-on to block them (although it would be nicer, if FF & Co already had a possibility to block certificates based on checksum, optional pinning etc.) and you might give the CA more time to officially revoke the certificate.
I would also suggest to publish the available information about the certificates once they have been revoked.
FTR: I strongly support Eddy's suggestion concerning full public disclosure of CP/CPS.
(Side note: it might be beneficial to work with the EFF SSL observatory (especially once they deployed their distributed approach in HTTPS Everywhere) to find suspicious certificates.)
Any company large enough to go to the hassle of getting a trusted
subordinate CA and have the knowledge necessary to deploy such a MITM
attack solution almost certainly knows what they're doing is wrong. I
don't see why they should be allowed to continue violating the policy
for months rather than switching off the interception until they have
another solution in place.
Given that subordinate CAs have the power to grant certificates for
any domain, I believe that our trusted root CA holders should have an
obligation to publicly publish a list of who they have granted
subordinate CAs to, and keep such a list up to date. (Although
ultimately, the root CA holder is responsible for the actions of their
subordinates).
> Note that the “<date TBD>” is proposed because any such customers are > probably very large enterprise customers who likely will have to bring > up a corporate certificate infrastructure [... ]I am > thinking that the date should be something between 2 and 3 months after > the official communication is sent.
While I would also prefer a much shorter time frame: what about at least a compromise if that is not possible? Require them to report the SHA1 fingerprint, subject, serial number within 2 weeks and publish the checksum somewhere. Then users could use an add-on to block them (although it would be nicer, if FF & Co already had a possibility to block certificates based on checksum, optional pinning etc.) and you might give the CA more time to officially revoke the certificate.
I would also suggest to publish the available information about the certificates once they have been revoked.
FTR: I strongly support Eddy's suggestion concerning full public disclosure of CP/CPS.
(Side note: it might be beneficial to work with the EFF SSL observatory (especially once they deployed their distributed approach in HTTPS Everywhere) to find suspicious certificates.)
the motivation for "give all CAs a grace period" is based on the assumption "there are several other CAs who are involved in the corporate-environment-MITM-business".
The assumption might be right or wrong. We don't know yet.
If we immediately execute the punishment, everyone will (morally rightful) expect that we repeat the punishment for any future CA being detected, with immediate effect - for all MITM activities that are currently still ongoing and that we will learn about in the future. (Who knows how many employees of such environments already made a backup copy of such a MITM certificate, can proof that the cert hasn't been revoked and is still valid as of today, and are waiting to submit until after we made such an ultimate decision, knowing that their submission causes end-of-business for such CAs?)
We don't know yet how many CAs would have to be punished. What if we'd have to punish a set of major CAs that has certified more than 50% of the secure web? If this unfortunate assumption were true, wouldn't we cause an immediate shutdown of a large percentage of the secure web and create lots of chaos? This is the dilemma we are facing. Under the assumption that such MITM uses are indeed limited to closed corporate environments, this immediate chaos, and the amount of potential economical harm caused, might be worse than the immediate benefit of shutting down the corporate internal watching. (Under the assumption that MITM is indeed limited to corporate environments, I'm willing to change my opinion 180° on the first proof of MITM outside of a corporate network made possible by one of the CAs in the Mozilla CA program.)
The use of MITM CA certs in corporate networks is an unethical practice and we should stop it as quickly as we can.
I still believe it's a good idea to grant a short grace period for CAs to learn about the new guaranteed punishment, because we clarify that MITM subCA behaviour is always absolutely unacceptable, even in controlled corporate environments, and give them an opportunity to act accordingly and stop it immediately.
I originally bought the argument that 2-3 months are a necessary period of time to allow for transitioning.
However, I very much like Jan Schejbal's new argument:
> a) They do not need to roll this out immediately, they just need to
> stop doing MitM attacks until they managed to roll it out
> b) They only need to roll out to clients to be MitM-ed, i.e. not all
> WiFi APs etc.
I agree with Jan's argument that the internal "MITM needs" of corporate environments aren't sufficient reason to allow for a long transition period. I agree the transitioning argument shouldn't play a role when making a decision for the length of the grace period. If a corporation depends on MITM practices involving trusted public CAs (instead of the cleaner solution of using a private CA), it's the coporation's problem that they will temporarily be unable to watch all employee's traffic, it doesn't matter for the public web community.
I still believe we need to give CAs a chance to investigate their list of issued subCA and make decisions for themselves, which subCAs they are willing to continue to trust (because they are 100% sure they have strong control) and which subCAs are "too risky" from now on, because an abuse performed by a customer could mean the immediate end of a major part of their CA business.
Maybe one month should indeed be a sufficient amount of time for CAs to make such assessment for their set of issued subCAs.
If, during this period of time, at least one more CA goes public, consequently revokes such MITM subCAs certificates, and promises to not do it again, then we have done something good for the security of the web. I agree with the argument made earlier, this scenario is better than having several large CAs decide that complete secrecy is the only chance left to save their business.
However, I would like to make everyone aware of an additional potential outcome.
After the grace period, what if we learn that Trustwave was actually the only CA that participated in the corporate MITM business?
Maybe we will learn that no other CA has the need to come clean?
Maybe all the other CAs in the Mozilla root program decide they have nothing to hide, and are not worried by the threat "Mozilla will remove you from the Mozilla CA program if we discover any of your subCAs is used by anyone for MITM practices"?
In my opinion, if this should happen, if we learn at the end of the grace period that Trustwave was actually the only CA involved in the corporate MITM business, because no other CA made use of the offer to come clean, because all CAs accept the rule "MITM detected and you're out", then we will still have the right to remove TrustWave, and under such circumstances we should probably do so.
> Require them to report the SHA1 fingerprint, subject, serial number within 2 weeks and publish the checksum somewhere.
In general I agree, it would be good if CA published the "subject name" of intermediate certificates. This means we'd learn who actually deployed such intermediates.
But I'm worried that it might be a problem for CAs to publish that, they might not be allowed to make customer relationships public because of contracts.
I'm worried the requirement to make the "subject name"s public immediately would unnecessarily delay the process of getting intermediates revoked and announced, because CAs might argue they have to check with lawyers first, etc.
I propose, our immediately call should be restricted to the details that are sufficient for blocking such certificates, in order to allow for a quick turnaround, and avoid giving CAs a legal argument for being unable to comply with our request.
We don't strictly require the "subject name" of the intermediate CA for blocking.
The "Issuer DN" and the "serial number" (binary encoding of both) are the usual primary key to identify certificates (at least in the NSS library) and should be sufficient for the purpose of blocking.
> The assumption might be right or wrong. We don't know yet.
I might be naive, but I don't expect it.
> The use of MITM CA certs in corporate networks is an unethical > practice and we should stop it as quickly as we can.
That's not the issue (I don't have an opinion about ethics that much), but it's not compliant to any stated policy, requirement and audit criteria. You have a policy in place, you made a promise to your users and you have to enforce your policy, that's all.
Is there really something to stop here? Where are the CA policies that disclose such a practice? In fact, where is Trustwave's policy that disclosed it? If there are CAs that violate their own polices and on purpose violate the requirements Mozilla set forth, nuke them. Or define a new set of requirements. Or do nothing.
But what you are really saying is that you believe there might be CAs that have violated the Mozilla CA policy (amongst others obviously) and you beg them to come in compliance with the policy. What if tomorrow yet another CA comes forth with yet another practice that violates some other aspects of the the policy? Beg them too? Send another communication, another grace period? It's starting to become a joke really.
Today I failed to post to this list via NNTP.
I had to switch to submission by email.
If you have attempted to send messages to this newsgroup by NNTP, then please check that your posting went through. If not, please resubmit using a different mechanism, e.g. by subscribing via https://lists.mozilla.org/listinfo/dev-security-policy
> Here is a proposed DRAFT of a CA Communication that I would like to send
> soon. I will greatly appreciate your constructive feedback.
All,
Thank you for your thoughtful and constructive feedback. Here is a second draft of the CA Communication.
It sounds like “<date TBD>” should be 2 months after the official communication is sent.
I thought about whether all of this should be included in one communication, or separated out into multiple communications. I would like to keep it as one communication with 5 action items to track for each CA.
Thanks,
Kathleen
===
Subject: Mozilla Communication: Action requested by <date 2 weeks out>
Dear Certification Authority,
This note requests a set of immediate actions on your behalf, as a participant in the Mozilla root program.
Please reply by <date 2 weeks out> to confirm completion of the following actions or state when these actions will be completed.
1) Subordinate CAs chaining to CAs in Mozilla’s root program cannot be used for MITM or traffic management of domain names or IPs that the party does not legitimately own or control, regardless of whether it is in a closed and controlled environment or not. Please review all of your subordinate CAs to make sure that they cannot be used in this way. Any existing subordinate CAs that can be used for that purpose must be revoked and any corresponding HSMs destroyed as soon as possible, but no later than <date TBD>. For each subordinate CA that is revoked, send me:
a) The certificate that signed the subCA. If it is a root certificate in NSS, then the root certificate's subject and SHA1 fingerprint.
b) The Serial Number of the revoked certificate.
c) The CRL that contains the serial number of the revoked certificate.
As a CA in Mozilla’s root program you are ultimately responsible for certificates issued by you and your subordinate CAs. After <date TBD> if it is found that a subordinate CA is being used for MITM, we will take action to mitigate, including and up to removing the corresponding root certificate. Based on Mozilla’s assessment, we may also remove any of your other root certificates, and root certificates from other organizations that cross-sign your certificates.
2) If you issue subordinate CAs to third parties, please add a statement to your CP/CPS committing that you will not issue a subordinate certificate that can be used for MITM or traffic management of domain names or IPs that the party does not legitimately own or control. Send me the URL to the updated document(s) and the impacted sections or page numbers.
3) Please scan all of your EV SSL certificates and revoke any that do not meet the EV requirements. This includes, but is not limited to maximum validity period of the certificate, subject naming, minimum key sizes, required extensions, and maximum expiration time of OCSP responses.
4) Certificates chaining to root certificates in Mozilla’s root program should not have MD5 algorithms or key sizes less than 1000. Please scan the certificates chaining to your root certificates in NSS, and revoke any certificates that contain small key sizes or MD5 algorithms.
5) The CA/Browser Forum has released the "Baseline Requirements for the Issuance and Management of Publicly Trusted Certificates,” which is available here: http://www.cabforum.org/. Discussions are in progress in the mozilla.dev.security.policy forum to update Mozilla’s CA Certificate Policy to add a requirement that CAs also meet these baseline requirements for issuance of SSL/TLS certificates. Please contribute to the discussions in the mozilla.dev.security.policy forum, and update your operations and documentation as needed to meet the baseline requirements by the effective date of July 1, 2012.
Participation in Mozilla's root program is at our sole discretion, and we will take whatever steps are necessary to keep our users safe. Nevertheless, we believe that the best approach to safeguard that security is to work with CAs as partners, to foster open and frank communication, and to be diligent in looking for ways to improve. Thank you for your participation in this pursuit.
Regards,
Kathleen Wilson
Module Owner of Mozilla's CA Certificates Module
> 12. Februar 2012 23:33:24 UTC+1 Kathleen Wilson:
>> Note that the “<date TBD>” is proposed because any such customers are
>> probably very large enterprise customers who likely will have to bring
>> up a corporate certificate infrastructure [... ]I am
>> thinking that the date should be something between 2 and 3 months after
>> the official communication is sent.
> While I would also prefer a much shorter time frame: what about at least a compromise if that is not possible? Require them to report the SHA1 fingerprint, subject, serial number within 2 weeks and publish the checksum somewhere. Then users could use an add-on to block them (although it would be nicer, if FF& Co already had a possibility to block certificates based on checksum, optional pinning etc.) and you might give the CA more time to officially revoke the certificate.
> I would also suggest to publish the available information about the certificates once they have been revoked.
> FTR: I strongly support Eddy's suggestion concerning full public disclosure of CP/CPS.
> (Side note: it might be beneficial to work with the EFF SSL observatory (especially once they deployed their distributed approach in HTTPS Everywhere) to find suspicious certificates.)
> On 02/13/2012 08:13 PM, From Kai Engert:
>> The assumption might be right or wrong. We don't know yet.
> I might be naive, but I don't expect it.
I'm quite sure there are more of CAs that issued certs for "traffic
management" based on the discussions in various lists.
We could ask Peter Gutmann, if Trustwave was the one he was talking
about. If it wasn't, he'll likely say "no", because it probably won't be
breach of the NDA. In the worst case we'll get another "you must be
joking, right?" answer ;-)
>> The use of MITM CA certs in corporate networks is an unethical
>> practice and we should stop it as quickly as we can.
> That's not the issue (I don't have an opinion about ethics that much),
> but it's not compliant to any stated policy, requirement and audit
> criteria. You have a policy in place, you made a promise to your users
> and you have to enforce your policy, that's all.
> Is there really something to stop here? Where are the CA policies that
> disclose such a practice? In fact, where is Trustwave's policy that
> disclosed it?
I peeked shortly the other day into Trustwave's CPS, Relying Party
Agreement/Warranty, they state in capitals: "TRUSTWAVE MAKES NO
REPRESENTATION OR WARRANTY AS TO THE BUSINESS PRACTICES OF THE TRUSTWAVE
SUBSCRIBERS." (This specific clause likely only covers monetary
compensation, but I have no idea if it could be twisted in court.)
Also, who has all the past documents (though there are _some_ old
versions listed)? They can change them at any time (I despise this
widespread contractual practice: "New version will be posted in your
local planning department in Alpha Centauri. It will be on display in
the bottom of a locked filing cabinet stuck in a disused lavatory with a
sign on the door saying 'Beware of The Leopard'".)
By looking at "Last-Modified" headers, CPS was changed in March 2011 and
RP Warranty in April 2009.
> Thank you for your thoughtful and constructive feedback. Here is a
> second draft of the CA Communication.
> ===
> 1) Subordinate CAs chaining to CAs in Mozilla’s root program cannot be
> used for MITM or traffic management of domain names or IPs that the
> party does not legitimately own or control, regardless of whether it is
> in a closed and controlled environment or not. Please review all of your
> subordinate CAs to make sure that they cannot be used in this way. Any
> existing subordinate CAs that can be used for that purpose must be
> revoked and any corresponding HSMs destroyed as soon as possible, but no
> later than <date TBD>. For each subordinate CA that is revoked, send me:
> a) The certificate that signed the subCA. If it is a root certificate in
> NSS, then the root certificate's subject and SHA1 fingerprint.
> b) The Serial Number of the revoked certificate.
> c) The CRL that contains the serial number of the revoked certificate.
I'd add:
d) the validity period (notBefore and notAfter) of the revoked certificate
> As a CA in Mozilla’s root program you are ultimately responsible for
> certificates issued by you and your subordinate CAs. After <date TBD> if
> it is found that a subordinate CA is being used for MITM, we will take
> action to mitigate, including and up to removing the corresponding root
> certificate. Based on Mozilla’s assessment, we may also remove any of
> your other root certificates, and root certificates from other
> organizations that cross-sign your certificates.
I'd like this to become reality, but it has potential to get stuck in
legal departments. For example, the CPSs for cross-signing certificates
I've seen explicitly state not being responsible for the CA they cross-sign.
> 4) Certificates chaining to root certificates in Mozilla’s root program
> should not have MD5 algorithms or key sizes less than 1000. Please scan
> the certificates chaining to your root certificates in NSS, and revoke
> any certificates that contain small key sizes or MD5 algorithms.
We could add the link you mentioned pointing to section 8:
> But what you are really saying is that you believe there might be CAs
> that have violated the Mozilla CA policy (amongst others obviously) and
> you beg them to come in compliance with the policy. What if tomorrow yet
> another CA comes forth with yet another practice that violates some
> other aspects of the the policy? Beg them too? Send another
> communication, another grace period? It's starting to become a joke really.
I don't see it as begging. I see it as "last chance to come clean or
enjoy joining the Diginotar bankruptcy club". AFAIK the greatest issue
in the past when delisting a CA was the potential threat of lawsuit
(setting rules should mitigate that).
My reasoning is:
1) Should Trustwave and other MitM-cert-issuing CAs be punished? Yes.
2) Would the yet-unknown CAs try to cover up their MitM certs if
threatened to be delisted now? Almost definitely yes. (It should be
noted here, that the Comodo fiasco would go unnoticed by public were it
not for Appelbaum's crlwatch:
https://bugzilla.mozilla.org/show_bug.cgi?id=643056)
3) Does knowing and blacklisting the MitM certs offer better protection
for users than hunting the CAs one-by-one later? I think so.
Comodo made a quick decision that public disclosure was the right thing to do, and we agreed a timeline with the major browser vendors to do just that. The only reason to delay public disclosure for ~1 week was to give the browsers time to patch.
Appelbaum just happened to discover independently what was going on before the agreed ~1 week had elapsed.
-- Rob Stradling
Senior Research & Development Scientist
COMODO - Creating Trust Online
> On 14/02/12 13:13, Ondrej Mikle wrote:
> <snip>
>> (It should be noted here, that the Comodo fiasco would go unnoticed by
>> public were it
>> not for Appelbaum's crlwatch:
>> https://bugzilla.mozilla.org/show_bug.cgi?id=643056)
> Absolute rubbish!!!
> Comodo made a quick decision that public disclosure was the right thing
> to do, and we agreed a timeline with the major browser vendors to do
> just that. The only reason to delay public disclosure for ~1 week was
> to give the browsers time to patch.
> Appelbaum just happened to discover independently what was going on
> before the agreed ~1 week had elapsed.
> Everyone with any common sense had to know that such certificates are
> not acceptable, and they should never have been issued.
Those who don't live in the Internet/CA/crypto world may well not be aware of this.
I can imagine the following logic at some big company:
- We have a problem. We need to either:
A) protect ourselves from data theft; or
B) comply with some regulatory requirement; or
C) know whether our employees are spending loads of time on Facebook
- We need a system which can analyse traffic
- This company sells them; buy one
- We need a thing called a certificate
- This company sells them; buy one
- Problem solved
I think it's unlikely that such companies know all the ramifications of purchasing such a certificate.
> a) They do not need to roll this out immediately, they just need to
> stop doing MitM attacks until they managed to roll it out
If the system is in place for regulatory compliance (and I believe there are circumstances where full monitoring of network traffic is necessary) then turning it off isn't an option.
> I do not see any reason why knowingly allowing MitM attacks would be a
> good idea.
Perhaps we just fundamentally disagree on this, but I think that if a company owns a network and wants to monitor all traffic on it, it has a perfect right to do so. It's their network. Don't like it, don't use it for secret stuff.
> I don't see it as begging. I see it as "last chance to come clean or > enjoy joining the Diginotar bankruptcy club".
I didn't propose removing any CA root - but enforcing the policy. There are various different ways and requirements that Mozilla can place on a CA that doesn't comply to the policy before removing it as a last resort.
> AFAIK the greatest issue in the past when delisting a CA was the potential threat of lawsuit
BS
> 1) Should Trustwave and other MitM-cert-issuing CAs be punished?
No - "punishment" isn't how I would call it, but attach strings, requirements and confirmations of whatever Mozilla wants to see implemented by Trustwave.
What I've seen so far is yet another "communication" to the CAs - however what I haven't seen is, which requirements it places on Trustwave today and now.
And CAs would take note on that much more than yet on another "communication".
> On 02/14/2012 03:13 PM, From Ondrej Mikle:
>> I don't see it as begging. I see it as "last chance to come clean or
>> enjoy joining the Diginotar bankruptcy club".
> I didn't propose removing any CA root - but enforcing the policy. There
> are various different ways and requirements that Mozilla can place on a
> CA that doesn't comply to the policy before removing it as a last resort.
Maybe you could give some suggestions. I've seens using "comply to
policy" and "enforce policy" many times, but I have only really vague
idea about real meaning behind those phrases (aside from what was
mentioned in Kathleen's letter).
>> AFAIK the greatest issue in the past when delisting a CA was the
>> potential threat of lawsuit
"When we wrote the Mozilla policy, we inserted that Mozilla had the sole
right to decide when to pull a root. When I suggested that (yes, blame
me now) I knew that any suggestion to pull a root would immediately
cause a counter-balancing lawsuit by CAs with cashflow in mind. (Which
would win, ask your lawyer how to stop anything with an injunction.)"
>> 1) Should Trustwave and other MitM-cert-issuing CAs be punished?
> No - "punishment" isn't how I would call it, but attach strings,
> requirements and confirmations of whatever Mozilla wants to see
> implemented by Trustwave.
Just to be clear here, by "punishment" I wasn't insinuating pulling
Trustwave's (or other CA's root/trust anchor) just yet. Nevertheless all
the MitM subCA certs should be published.
I don't know what tools are available for Mozilla to "enforce policy".
How you prove non-existence of MitM cert anyway?
>From my personal experience, telling a CA to revoke cert with 512-bit
that could be used for code-signing (had the "right" KU and EKU, trusted
by Mozilla and Microsoft) was akin to chatting with /dev/null. It was
around the time of the signed-malware case; those certs were not yet
known by anyone else (I sent the certs to Mozilla security team before
sending message to CA directly as well).