Microsoft Security Advisory (2798897)
Microsoft is aware of active attacks using one fraudulent digital certificate issued by TURKTRUST Inc., which is a CA present in the Trusted Root Certification Authorities Store. This fraudulent certificate could be used to spoof content, perform phishing attacks, or perform man-in-the-middle attacks. This issue affects all supported releases of Microsoft Windows.
TURKTRUST Inc. incorrectly created two subsidiary CAs (*.EGO.GOV.TR and e-islem.kktcmerkezbankasi.org). The *.EGO.GOV.TR subsidiary CA was then used to issue a fraudulent digital certificate to *.google.com. This fraudulent certificate could be used to spoof content, perform phishing attacks, or perform man-in-the-middle attacks against several Google web properties.
To help protect customers from the fraudulent use of this digital certificate, Microsoft is updating the Certificate Trust list (CTL) and is providing an update for all supported releases of Microsoft Windows that removes the trust of certificates that are causing this issue.
Source:
Microsoft Security Advisory (2798897): Fraudulent Digital Certificates Could Allow Spoofing
See also:
Microsoft Security Advisory: Fraudulent digital certificates could allow spoofing