A day ago (Tuesday, 6th September) Estonian Information System Authority was informed about a security vulnerability in the electronic chip of Estonian ID cards.
Use of electronic signatures is very common in Estonia. This includes all sorts of legal contracts. Estonia uses the same electronic cryptographic system for online electronic voting. An electronic signature from an ID card is fully binding. It has the same power as a manually written signature.
The vulnerability affects 750000 ID cards issued in the last 3 years. Estonian population is 1.4 million. Estonian ID card is mandatory for every citizen.
Henrik Roonemaa, a well-known Estonian journalist has put together an article from various sources of information. It is published in Estonian. The important points are:
- The cost of breaking one card for signing is 40k EUR.
- At least one card has been broken for demonstration purposes.
This shows the severity of the situation. The vulnerability is believed due to the process of generating private and public keys inside the card chip. The weakness allows to deduce the private key from the public key. The list of all public keys was publicity available until Tuesday when it was taken down. Full details of the vulnerability have not yet published.
You get the full power to forge a perfect signature once you gain access to the private key. The electronic signature would be extremely hard to disprove as such attack was deemed practically impossible by experts.
Estonian government says that the issue won't affect the Estonian state as a whole. They say that it would only happen when someone put 60 billion EUR into work to break most of the 750000 signatures. Estonia is worth way more than 60 billion EUR. The government has not yet addressed the issues of individual citizens getting targeted by attacks using this vulnerability.
New cards will have to be issued to fix the vulnerability.
It has not been confirmed that a card has been actually broken. The issue might then be a lot less severe than thought. The text has been removed from the article.
It takes about 10-12 hours to crack a card according to the former Estonian president Toomas Hendrik Ilves. Ilves says that this is based on facts. The information comes from an article published in the daily newspaper Postimees. The article also states that the vulnerability is between the chip hardware and the software directly communicating with the chip.
The current solution is to replace certificates on all vulnerable cards. I have done this to mine as it was vulnerable.