After Mozilla inquiry, Apple untrusts Chinese certificate authority

After an upcoming update MacOS and iOS will not trust new certificates issued by WoSign

Following a Mozilla-led investigation that found multiple problems in the SSL certificate issuance process of WoSign, a China-based certificate authority, Apple will make modifications to the iOS and macOS to block future certificates issued by the company.

Although there is no WoSign root certificate in Apple's trusted certificate store, a WoSign intermediate CA certificate is cross-signed by two other CAs that Apple trusts: StartCom and Comodo. This means that until now Apple products have automatically trusted certificates issued through the WoSign intermediate CA.

Because WoSign experienced multiple control failures in their certificate issuance processes for the WoSign CA Free SSL Certificate G2 intermediate CA, "we are taking action to protect users in an upcoming security update," Apple said in support notes for both iOS and macOS. "Apple products will no longer trust the WoSign CA Free SSL Certificate G2 intermediate CA."

The ban is only for future certificates issued by WoSign and not for those that have already been issued and published to public Certificate Transparency (CT) log servers by Sept. 19. Those existing certificates will continue to be trusted until they expire, are revoked, or Apple decides to ban them at a later date.

This is similar to the decision that Mozilla's CA team is considering after discovering multiple problems at WoSign, including mis-issuing of certificates and a strong suspicion, backed by evidence, that the CA issued SHA-1-signed certificates after Jan. 1 and then back-dated them in violation of industry rules.

"Mozilla’s CA team has lost confidence in the ability of WoSign/StartCom to faithfully and competently discharge the functions of a CA," the Mozilla team said in a detailed analysis of the incidents. "Therefore we propose that, starting on a date to be determined in the near future, Mozilla products will no longer trust newly-issued certificates issued by either of these two CA brands."

The inclusion of StartCom, an Israel-based CA, in this decision is due to the fact that WoSign silently acquired StartCom in November 2015. Although WoSign said in September that the two companies are operated and managed independently, there is evidence that StartCom has been using WoSign's certificate-issuing infrastructure and processes.

In its own analysis and response, WoSign claims that only 8 SHA-1 certificates have been incorrectly issued after the SHA-1 cutoff date of Jan. 1, 2016, and that those incidents were the result of a bug in its system and API.

"WoSign remains committed to continually evolve our technology, processes, and offerings to help keep our customers and the Internet safe," said in its final report after the investigation. "We believe that the steps we have taken will ensure that this type of incident never happens again, and we believe that full support for CT is our commitment of supervision."

Join the PC World newsletter!

Error: Please check your email address.

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Lucian Constantin

IDG News Service
Show Comments

Most Popular Reviews

Latest News Articles


GGG Evaluation Team

Kathy Cassidy


First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni


For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell


The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi


The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott


My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?