Google Blog - Maintaining digital certificate security

On April 1, 2015, Google stated that one of the Value Added Distributers of CNNIC miss-used the digital certificates that leads Chrome to revoke the certificates of CNNIC and Firefox to revoke the certificates issued by MCS Holdings.

MCS Holdings is an Egypt-based intermediate certificate authority that operated under the authority of CNNIC.

Google's blog on March 23, 2015 :
http://googleonlinesecurity.blog ... icate-security.html

MCS Holdings response to Google blog on March 25, 2015 :
http://www.mcsholding.com/MCSResponse.aspx