Some folk have asked me for more details about the DigiNotar breach after my brief appearance on Al Jazeera this morning. So here are the notes I prepared for the segment. Links at the bottom.
web security certificates are digital IDs issued by companies entrusted with making sure they are given to the right company or organisation. It allows a user to set up a secure connection between their computer and the organisation's website. Browsers will show a little lock or some other icon to signify the certificate has been found and is trusted.
Hackers broke into a Dutch company called DigiNotar, itself owned by US firm Vasco Data Security, in mid June. DigiNotar is one of hundreds of companies around the globe called certificate authorities that issue these authentication certificates. Browsers contain a list of which CAs they can trust.
These hackers would have been able to steal existing certificates or generate their own, meaning they could now, with the help of an Internet Service Provider, launch what are called Man in the Middle Attacks--meaning they could intercept traffic, a bit like tapping a telephone.
DigiNotar noticed that something was amiss in July, but didn't realise the extent of the breach until late August, by which time more than 500 (531) fake certificates were issued. While some cover domains like the CIA and MI6, these are probably just distractions. The key ones are a dozen issued for domains like Google, Facebook and Skype.
Why do we think this was about Iran?
Studies of the validation requests--browsers pinging DigiNotar to confirm the certificate's authenticity--showed that during August the bulk--maybe 99%--of the traffic was coming from Iran. When the certificates were eventually revoked, Iranian activity dropped.
Moreover the attackers left some quite obvious clues. They left calling cards: transcribed Farsi which translates into slogans such as "I will sacrifice my life for my leader." "unknown soldier"
Why might Iran be interested?
Well, we now know that a lot of countries like Syria intercept ordinary Internet traffic through something called Deep Packet Inspection. This means that the government is basically snooping on web traffic. But when that traffic passes through these secure connections, it's much harder. So the holy grail of any internet surveillance is to get a hold of those certificates, or work around them. This is a brazen attempt to do this.
All Internet traffic in Iran has to go through a government proxy, making this kind of attack much simpler. The government ISP just uses the certificate to pretend to be Google, or whatever, and then passes the traffic on.
Is it the government?
This is harder to confirm. The Dutch government is investigating this. A similar attack took place against an Italian CA in March, and it shows similar fingerprints.
But the fact that the certificates were stolen and then used seems to suggest some official connection.
What could they have discovered?
Quite a lot. All the traffic that was intercepted could be deciphered.. meaning all browsing and emails. But it also may have captured cookies, meaning passwords, which would have made it easy to hack into target accounts and sniff around old emails, dig out other passwords, or hack into associated accounts, such as Google Docs.
Moreover, some of the certificates compromise something called The Onion Router, a service which anonymizes web traffic. Though TOR itself wasn't compromised the certificates could convince your browser you were talking to TOR, whereas in fact you'd be talking to the attacker.
Should other people be worried?
Yes, Some browser developers have been more forthcoming than others; Google Chrome and Firefox have been quick to respond. Others less so. If you're in Iran or think you may be targetted, it's a good idea to change your password, and to check that no one has altered your forwarding details in your email account. You should also upgrade your browser to the latest version, whatever browser you use.
DigiNotar made some horrible mistakes: one Windows domain for all certificate servers, no antivirus, a simple administrator password. There were defaced pages on the website dating back to 2009. One has to wonder what other certificate authorities are similarly compromised. We rely on these companies to know what they're doing. They're the top of the food chain, in the words of one analyst.
We should now be looking closely at the previous breaches and looking for others. This is a ratcheting up of the stakes in a cyberwar; this kind of thing has real world impact on those people who thought they were communicating safely and will now fear the knock on their door.
In the future this is likely to lead to a change in the way certificates are issued and checked. I don't think DigiNotar is going to survive this, but I think a bigger issue is bound to be how this security issue is handled. I think governments which look to the Internet as a tool for democratic change need also to be aware of just how dangerous it is to encourage dissidents to communicate online, whether or not they're being careful.