Salvaging Digital Certificates

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One year ago, Gmail users in Iran woke up to a chilling prospect: Their sensitive and supposedly secure communications on Google's email program may have been tapped by unknown parties. A phony digital certificate in Google's name was used to impersonate the site and let the culprits mount a "man in the middle" attack to intercept and decrypt email sent to Google's servers before passing the messages along to the intended recipients.

In the search for the source of the phony certificate, all eyes turned to DigiNotar, a certificate authority in Beverwijk, Netherlands. DigiNotar admitted that it had been the victim of a cyberattack a month earlier whereby the attackers generated hundreds of bogus certificates in the names of some of the Internet's most trusted brands, including Google, Yahoo, Skype and the anonymity network Tor. Use of the fraudulent certificates was concentrated among Iranian users, leading to speculation that the attack was linked to that country's intelligence services, which have been cracking down on political dissidents.

The DigiNotar attack was the worst security compromise at a certificate authority to date. But it was hardly the only such attack. It came just months after an attack on a business affiliate of Comodo, a New Jersey CA. In that incident, the attackers generated phony certificates also in the names of prominent online brands.

These successful attacks were earth shaking because digital certificates and the encryption keys they represent are the bedrock of Internet communications. They secure everything from VPN connections to protocols such as TLS (Transport Layer Security) and SSL (Secure Sockets Layer) that protect billions of Web sessions and online transactions daily. At the heart of this system is a global public key infrastructure network of some 300 CAs entrusted with issuing certificates to individuals and organizations.

Certificate authorities are gatekeepers. They verify the identities of individuals and organizations before issuing digital certificates that contain the public and private encryption keys used to secure online exchange of information.

At least that's how it's supposed to work. As the DigiNotar attack revealed, CAs aren't Fort Knox-style identity vaults but rather are businesses subject to their own security mishaps. In the last year, CAs have come under attack from sophisticated and possibly nation-backed hacking crews, exposing security lapses and poor internal controls.

The current system leaves security-conscious businesses in a pinch. More than ever, they need secure and reliable identity services to back up their growing online presences, but the system in place is more vulnerable than ever.

What's to be done? Many experts say certificate technology still has a future and that security-conscious organizations can protect themselves by understanding the gaps in the system and taking common-sense steps to avoid them.