Diginotar hacker threatens SSL attacks in US, Europe and Israel

THE IRANIAN HACKER who broke into multiple certificate authorities (CAs) has threatened to launch man-in-the-middle (MitM) attacks in US, Europe and Israel using the rogue SSL certificates in his possession.

The recent breach at Dutch certificate authority Diginotar was discovered because a rogue *.google.com cert issued by the company was used in a MitM attack in Iran against Gmail users.

The presence of rogue certificates in the wild has very bad implications for the public key infrastructure (PKI) used to establish trust online. However, in practice, these certificates can only be abused to impersonate web sites if attackers control the DNS servers used by their victims.

Targeting a particular individual or company isn't hard because it only involves hacking into a local network or a server, but targeting users en masse requires control of large and better protected internet gateways, which is not so easy to achieve.

Large-scale surveillance operations have been seen before in Iran, Tunisia, Egypt and Syria, where the government controls the internet infrastructure, but not in countries where internet peering is managed by private companies.

Nevertheless, the possibility of a hacker capable of breaking into certificate authorities also compromising major ISPs should not be easily dismissed, especially since he apparently is very determined.

"This time attack was limited to Iran, next time, I'll own as more as gateways in Israel, USA, Europe, as more as ISPs and attack will run there. You know man, I give promises and I keep them," the hacker warned, pointing out that he kept at his work after the Comodo breach and hacked into more CAs.

But not only has he threatened to hack into ISPs, he has claimed to have already started. He gave LMi.net, a small DSL and hosting provider based in Berkeley, CA, as example.

"For an example ask a little from LMI.NET Berkley's ISP, ask about user Todd and password [xxxxxxx] (for example), ask if they detected that I was owned their all Linux boxes and I got access to their DNS servers," the hacker wrote.

He also reiterated that despite sharing some certificates with people in Iran - probably those used in country-wide MitM attacks - he acted alone in hacking Diginotar and other yet-to-be-named CAs.

The hacker also promised to release all emails, database backups and customer details of Startcom, a CA compromised earlier this year, and, as far as the Globalsign CA goes, he claimed to have the private key of the company's domain name and a copy of its server.

Security experts recommend that users access web services only over HTTPS, a protocol that combines HTTP with SSL, in order to protect themselves from man-in-the-middle attacks. But if the attacker also has valid certificates for those services, this advice carries little weight.

In such cases, solutions like Moxie Marlinspike's Convergence can help. Convergence checks certificates received by the browser with the ones downloaded from the same websites by third-party notary servers. Under normal circumstances, these certificates should match. If they don't, an attack might be under way. µ