Web authentication authority StartSSL was forced to shut down after a security breach of its Israel-based parent company StartCom last week.
StartCom did not detail how the breach occurred and said only that it had suspended the issuance of new digital certificates.
“Due to a security breach that occurred at the 15th of June, issuance of digital certificates and related services has been suspended. Our services will remain offline until further notice,” the company said in an online "maintenance" notice.
The company said its existing certificates were not affected by the breach, nor were visitors to its web sites.
The attack follows a security breach of web authority Comodo in March in which hackers had compromised two resellers and issued forged digital certificates for nine web sites including Google.com, Google mail, Mozilla Addons, and three login sites for Yahoo Skype and Microsoft.