Secure IT Foundation

Archive for September 2011

It has been difficult to avoid the news stories regarding a Dutch company called Diginotar and the prediction of the end of Internet security as we know it. Some stories have been based on facts, while others have clearly been written just to sell news or by those who have little comprehension of how the Internet and computers work.

To help explain the saga we have written a FAQ based on queries we have received.

Who is Diginotar?

Diginotar is a private company set up in 1998 to supply electronic identity management products including the issuing of ‘digital certificates’ for secure Internet transactions. In 2004 the Dutch government trusted Diginotar with the responsibility for providing digital certificates for all government / citizen interactions under a scheme called ‘PKIoverheid‘.

What are digital certificates?

Digital certificates are part of the technology which allows a home computer user to communicate securely over the Internet for important transactions like banking, paying bills, interacting with government services online etc.

Each time you see padlock in your browser, or the address bar turns green or you see https:// in the address you browser has established a secure channel over the Internet using complex mathematics to provide encryption.

If you think that most of your Internet activity does not involve using a secure channel, you can liken it to using a postcard to send a message to a friend in the real world. Anyone can read the message between you and your friend. This may be fine for arranging a meet in a bar but you would not the world to be able to view your banking transactions in the same way. This is where digital certificates come in, to provide secure electronic communications.

Each major company who wants you to communicate with them purchase digital certificates from companies like Diginotar, called Certificate Authorities officially. These Certificate Authorities verify the identity of the company wishing to buy a certificate, and issues the company with a unique code. When you want to establish a secure channel with your bank, your browser receives part of the unique code and checks that is really does belong to the company it claims to be. This proves that you are talking to the right company and allows a secure channel to start.

How does my browser know the identity of my bank?

Your browser e.g. Google Chrome, Apple Safari, Mozilla Firefox, Microsoft’s Internet Explorer etc all contain a list of trusted Certificate Authorities including Diginotar, each represented by a unique code. These companies around the world are trusted to provide digital certificates, some government owned but mostly private companies.

When your browser wants to verify the identity of the company or organisation e.g. a bank, it obtains the unique code from the digital certificate for the bank and mathematically checks it that it is valid with the unique code stored by the browser for the issuing certificate authority. If all checks pass then a secure channel is started. The proper name for this secure channel is an ‘SSL‘ connection.

The digital certificate gives you trust that you are communicating with the right organisation or company. Extra checks are made for a scheme called Extended Verification SSL certificates. When used, these ‘EVSSL‘ certificates are the type that make your browser address bar change colour to green, which highlights the verified nature of the company you are communicating with.

So what actually happened?

Based on the information published by Fox-IT BV, a major Dutch computer forensics company sited close to the Secure IT Foundation base in Rotterdam. It seems that hackers gained access to Diginotar’s internal computer systems as early as 6th June 2011. The hackers then attempted to make their own digital certificates. On the 10th July they succeeded in making a certificate which allow them to impersonate Google. The hackers continued for 10 more days making hundreds of digital certificates for major companies and computer systems.

Finally a security breach was detected by Diginotar on the 22nd July and an unnamed security company was called in to report, which they did on 27th July 2011. The same day, other security experts began to report unusual use of Google’s digital certificate and the next day traced it and it was being used in Iran. Diginotar went public on the security breach on the 30th August 2011, with the consequence that Diginotar’s validity as a certificate authority has been revoked by most browsers in recent updates.

While information is still being gathered and full facts may never be known publicly, it appears that the Iranian authorities have been able to intercept ‘secure communications’ with any of the companies impersonated by these rogue digital certificates by anyone using an Iranian computer network for about a month. In addition there was a potential for people outside of Iran to have been redirected to websites under the Iran authorities control, allowing for interception to occur to non Iranian citizens.

A similar attack on another certificate authority was made earlier in March 2011 on a US company called Comodo, which Comodo blamed fully at the Iranian authorities. However in this case only 9 rogue digital certificates were produced and the incident was stopped in a much shorter time frame than Diginotar.

How does this affect my home computer?

You may have noticed Mozilla and Google updated their browsers recently and Microsoft issued a patch via Windows Update. These changes remove the use of Diginotar as a valid certificate authority. If you visit a website using on of the rogue digital certificates then you should get a message not to trust the website you are communicating with. If you see a browser warning about the website’s authenticity then it is best not to continue the session and seek expert advice.

Outside of The Netherlands and Iran, most people will not see any impact from this security breach. Secure communications in Iran have become significantly harder but the most affect country so far is The Netherlands. Diginotar also managed part of the PKIoverheid system for secure Government communications so there has been some disruption to the service while new digital certificates have been issued to replace Diginotar supplied certificates. Thankfully the Dutch government had the sense to use multiple suppliers so the digital certificates issued by Diginotar have been replaced by one of the other three accepted certificate providers, without collapsing the whole Dutch system.

Is the problem now solved?

The dust has yet to settle and there are claims that other certificate authorities like Diginotar have also been compromised, however until new information is confirmed it does appear that the matter has been finalised. Diginotar’s continuing ability to trade is certainly going to be questioned as the initial findings from Fox-IT show Diginotar to be well below best practice for a security business.

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