[cabfpub] A few technical details about the case by TURKTRUST
Rick_Andrews at symantec.com
Fri Jan 4 19:40:19 UTC 2013
Thank you for providing this detailed information.
I have one concern about the post process control you’ve put into place. You say that it will check the basicContraints value against the respective certificate policy. I’m worried that if that test profile gets put on the production system again, and certs are issued against it, your post process control will not alert you, because the test policy would say “add basicConstrains cA=true” and that would match the issued certificate.
I think a safer approach would be to have a separate system for generating roots and intermediate CAs that need basicConstraints cA=true. Or, assuming you rarely create roots and intermediates on the production system, you might consider changing your post process control to alert you whenever a cert is issued with cA=true (no matter what the cert profile says). It will warn you whenever you legitimately create a root or intermediate (and you know you can safely ignore those). But if it ever alerts you when you were not intentionally creating a root or intermediate, you would know that the system must immediately be checked.
From: public-bounces at cabforum.org [mailto:public-bounces at cabforum.org] On Behalf Of mert.ozarar
Sent: Friday, January 04, 2013 7:33 AM
To: public at cabforum.org
Subject: [cabfpub] A few technical details about the case by TURKTRUST
Please find some critical points below about the root cause of the instance:
• The case occurred in August 2011 during a software migration operation, before the first successful ETSI TS 102 042 audit which took place in November 2011. The sequence of events that led to the mistaken issuance of two certificates can be best summarized as follows:
• Prior to June 2011, the certificate profiles on the production system were exported to the test system, containing a particular number of certificate profiles.
• For the sake of testing purposes, 2 more profiles were added that contain CA extensions.
• In the meantime, the production system was also updated to meet the need of demand to contain 3 more SSL certificate profiles. Hence the production system and the test system appeared to have different number of profiles by one, and the two sets matched only in the profiles at the date of the first data migration.
• The tests were completed before June 30, 2011. It was the unfortunate event that the production system was patched with the profiles in the test system, which had happened to contain 2 wrong profiles and lacked 3 correct profiles.
• The wrong profiles were only used on August 8, 2011 to issue those two faulty certificates which were certainly not intended to be sub-CA certificates.
• A certificate request on the 10th of August had called the use of one of the missing profiles, which was drawn to attention by a thrown exception. In order to fix this the whole set of certificate profiles was this time replaced to contain all correct profiles. Therefore the problem had been fixed once and for all although the unfortunate event that the certificates were mistakenly issued remained hidden.
It is assured that, this clearly identifies the root cause that led to the generation of faulty certificates. All related data resides in archives, and the sequence was all traced back to understand what really had happened. The system had been finally updated on October 17, 2011 and went through a successful ETSI TS 102 042 audit by KPMG on November 2011.
Although the system is now immune to any such kind of errors, further preemptive measures are implemented as described below:
One is a post process control for the certificates issued; the other is a run time control checking the certificate profile for end users.
Via the post process control, the validity period, basic constraints, CRL distribution point, Authority Info Access (AIA) and the other profile details are checked after certificate generation according to the certificate requirements coming from respective certificate policies before the certificate is delivered to the end customer. The post process control is planned as a separate and independent service from the certificate generation module of the CA software.
Via the run time control, the basic constraints are restricted to the end user certificates.
Both controls have already been implemented.
All OCSP requests and CRL data have already been analyzed to detect any anomaly during the entire period. The data revealed no anomaly at all.
The following issues are also worth considering at the moment:
1) One of the mistakenly issued certificates has been revoked before putting into use upon the request of the customer.
2) The other certificate was reported to sign a fraudulent certificate (*.google.com<http://google.com>) on December 6, 2012.
3) Before the December 6, 2012, the certificate was installed on an IIS as a web mail server.
4) On December 6, 2012, the cert (and the key) was exported to a Checkpoint firewall. It was the same day as the issuance of the fraudulent certificate (*.google.com<http://google.com>).
5) The Checkpoint firewall was said to be configured as MITM. It appears that the Checkpoint automatically generates MITM certificates once a CA cert was installed (http://www.gilgil.net/communities/19714)
6) The second certificate was immediately revoked as soon as it was brought to TURKTRUST’s attention by Google on December 26, 2012.
7) The available data strongly suggests that the *.google.com<http://google.com> cert was not issued for dishonest purposes or has not been used for such a purpose.
8) There is certainly not a bit of data to show an evidence of a security breach on TURKTRUST systems.
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