Blocking Trust for WoSign CA Free SSL Certificate G2
Certificate Authority WoSign experienced multiple control failures in their certificate issuance processes for the WoSign CA Free SSL Certificate G2 intermediate CA. Although no WoSign root is in the list of Apple trusted roots, this intermediate CA used cross-signed certificate relationships with StartCom and Comodo to establish trust on Apple products.
In light of these findings, we took action to protect users in a security update. Apple products no longer trust the WoSign CA Free SSL Certificate G2 intermediate CA.
To avoid disruption to existing WoSign certificate holders and to allow their transition to trusted roots, Apple products trust individual existing certificates that were issued from this intermediate CA and published to public Certificate Transparency log servers by 2016-09-19. They will continue to be trusted until they expire, are revoked, or are untrusted at Apple’s discretion.
As the investigation progresses, we will take further action on WoSign/StartCom trust anchors in Apple products as needed to protect users.
Further steps for WoSign
After further investigation, we have concluded that in addition to multiple control failures in the operation of the WoSign certificate authority (CA), WoSign did not disclose the acquisition of StartCom.
We are taking further actions to protect users in an upcoming security update. Apple products will block certificates from WoSign and StartCom root CAs if the "Not Before" date is on or after 1 Dec 2016 00:00:00 GMT/UTC.
About trust and certificates
Each macOS Trust Store listed below contains three categories of certificates:
- Trusted certificates establish a chain of trust that verifies other certificates signed by the trusted roots—for example, to establish a secure connection to a web server. When IT administrators create Configuration Profiles for macOS, these trusted root certificates don't need to be included.
- Always Ask certificates are untrusted but not blocked. When one of these certificates is used, you'll be prompted to choose whether or not to trust it.
- Blocked certificates are believed to be compromised and will never be trusted.