Web authentication authority suffers security breach

Counterfeit certificates sought for high-profile sites

Yet another web authentication authority has been attacked by hackers intent on minting counterfeit certificates that would allow them to spoof the authenticated pages of high-profile sites.

Israel-based StartCom, which operates StartSSL, suffered a security breach that occurred last Wednesday, the company said in a tersely worded advisory. The certificate authority, which is trusted by the Microsoft Internet Explorer, Google Chrome, and Mozilla Firefox browsers to vouch for the authenticity of sensitive websites, has suspended issuance of digital certificates and related services until further notice.

Eddy Nigg, StartCom's CTO and COO, told The Register that the attackers targeted many of the same websites targeted during a similar breach in March against certificate authority Comodo. The hackers in the earlier attack managed to forge certificates for seven addresses, including Google mail, www.google.com, login.yahoo.com, login.skype.com, addons.mozilla.com, and Microsoft's login.live.com.

The earlier breach touched off a frantic effort by the world's biggest browser makers to blacklist the counterfeit credentials before the hackers could use them to create spoof websites that contained a valid cryptographic stamp validating the sites' authenticity. It took more than a week for the fraudulent credentials to be blocked in all browsers, and even then, many widely used email programs still weren't updated.

The hackers behind the attack on StartCom failed to obtain any certificates that would allow them to spoof websites in a similar fashion, and they were also unsuccessful in generating an intermediate certificate that would allow them to act as their own certificate authority, Nigg said in an email. The private encryption key at the heart of the company's operations isn't stored on a computer that's attached to the internet, so they didn't get their hands on that sensitive document, either, he said.

Last week's attack is at least the fifth time an entity that issues SSL, or secure sockets layer, certificates has been targeted. In all, four of Comodo's resellers have suffered security breaches in the past three months.

The susceptibility of CAs to hackers represents one of the many significant vulnerabilities of the SSL system, which serves as the internet's foundation of trust. Once a CA's root certificate is included with a browser, it can be responsible for validating tens of thousands or hundreds of thousands of individual websites. That makes it impractical to remove the root certificate even if there is good reason to be wary of it.

Nigg declined to state how many certificates StartSSL has issued during its tenure, but he did say it is among the top 10 issuers. It is unclear when the CA will resume services. ®

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