What is Heartbleed and why is it different from just another cybersecurity vulnerability?

We have all, to a large degree, become numb to the constant stream of cybersecurity vulnerabilities and mass of patches forced upon us each month. As our IT systems become ever more complex and the code behind them ever longer, so too does the likelihood that the code will contain an unknown security vulnerability that could be exploited by hackers.

If a security vulnerability is discovered in the operating system of your Windows laptop for example, it's a simple case of Microsoft creating a patch and making it available for download so that you can fix the vulnerability before someone creates an exploit and turns your laptop into a zombie machine used for some nefarious purpose.

The theory is that if you patch quickly and you run anti-virus/anti-malware software you should be fairly safe. Systems running other operating systems, Apple OS X or Linux for example, are much newer than Windows, have less legacy code and less vulnerabilities, and by and large are smaller targets for hackers. Vulnerabilities are usually unique to an operating system or application, and therefore only affect a subset of Internet users.

Heartbleed is a little different. It's a vulnerability in the server security component designed to protect web-based traffic and a heap of other communications by encrypting and protecting the data going back and forth. The security is provided by Secure Sockets Layer/Transport Layer Security (SSL/TLS), which makes the difference between an HTTP and HTTPS address in the URL or address bar of your web browser. It also provides the green padlock on some browsers to signify that it's safe to enter confidential information, such as your name, address or credit card number. As mentioned earlier, SSL/TLS is also used several other ways, but its use in securing web traffic and e-commerce is ubiquitous and global.

A sudden and protracted widespread loss of confidence in the ability of users to interact securely with websites would have far reaching impact to Internet commerce, online banking, auction and travel websites and, perhaps topical for this time of year, in the United States and Canada, tax returns. In fact on Friday the Canadian government turned off the ability to submit tax return information online until it had a chance to assess the security of its systems.

Governments and commercial business now rely heavily on the ability to conduct business via the Internet so reluctance by consumers to also conduct business this way could have a massive impact on national and potentially global economies. This is why Heartbleed is SO significant above all other recent bugs and why a small error in the code behind TLS could possibly slow the world economy.

Of course this is a bit of a doomsayer view and in all likelihood, vulnerabilities will be patched within days the world over and security restored to the web and e-commerce. Two issues remain, however. First, the vulnerability in question has existed in certain versions of OpenSSL for two years.‘Should’ anyone have discovered this and exploited it to their own nefarious purposes, then there ‘could’ be all kinds of identity theft, and credit card and banking fraud, in addition to a heap of other problems related to the theft of Personal Identity Information, Protected Health Information and other confidential information.

The second issue is that consumers have been lulled and courted into using the Internet for the past 25 years on the promise that it was secure and that their information and finances were protected. This has allowed companies and governments to adopt more efficient and cost effective models of doing business that could now be challenged by a loss of confidence amongst their consumers. Depending upon media hype and whether anyone really was compromised, this could have a long-standing impact on the growth of business in this area.

What is the Heartbleed bug exactly?

It's a bug in certain versions of the ‘heartbeat’ feature of the TLS protocol used by OpenSSL that affects roughly two-thirds of the web servers that power the Internet. Hence the “Heartbleed” name. It's programming error was pushed to web servers over the past two years as they were upgraded to newer versions of OpenSSL and could affect the protection of the encryption keys and certificates used to identify users and to validate websites. It affects OpenSSL versions 1.0.1 released in December 2011 through 1.0.1f, which was until very recently the current version, along with certain beta versions of 1.02.

It doesn't affect Microsoft or Apple web servers, but it does affect a very large number of Apache web servers, which run mainly on Linux or Unix.

The heartbeat vulnerability was discovered a month ago and kept quiet while a patch was written and provided to systems administrators. Widespread publication of the Heartbleed vulnerability took place April 7th, and ever since there has been frantic activity by systems administrators and security professionals to patch systems before they could be compromised.

The OpenSSL 'Heartbeat' feature is used to maintain state and session information on users while they read, process or fill out web pages. It avoids a nasty time-out message and the need for the user to re-enter information again. Essentially it sends a 'heartbeat' back and forth to the web browser to see if the user is still there or not.

Instead of validating the advertised size of the heartbeat payload that OpenSSL writes to its memory, buggy versions of OpenSSL read back the payload from its first byte in memory to the length advertised for the heartbeat payload. Thus non-heartbeat information stored in memory is released if the advertised size of the payload is falsely provided. This is dangerous because that memory could contain confidential information posted by a user: passwords, account information, credit card numbers or , much worse, the encryption keys used to protect the entire server.

A simple exploit of the vulnerability thus works on the basis on passing false heartbeat information to a web server in order to retrieve information stored in its memory. It does this 64Kb at a time. 64Kb might not sound like a lot of memory but its more than enough to capture all the information a hacker could want and what’s more, the exploit can be run time and time again pulling information from affected web servers.

Even more worrying, it appears that exploiting this bug leaves no trace in the server’s logs, so there’s no easy way for a system administrator to know if servers have been compromised.

Rather than try to explain the technical details behind the vulnerability let me show you a video blackboard explanation of the vulnerability and potential attack by Zulfikar Ramzan, MIT Ph.D. and CTO of cloud security firm Elastica, this video does a great job of explaining things in easy to understand graphical terms.

So what should you do to protect yourself?

First, don't panic. Systems administrators and cybersecurity professionals have spent the last few days reviewing and patching their web servers and other systems reliant upon TLS to remove this vulnerability. They have also changed the encryption keys used on these servers. Some web sites that have been exposed have instituted a password reset, so that any passwords that users were using can no longer be used to access secure content, just in case these have been compromised.

It may take a few more days or even a another week or so for systems administrators to patch the majority of vulnerable systems - particularly those overseas where the message may take longer to reach. Many systems - those not running the vulnerable OpenSSL code - of course do not need patching as they were never at risk.

When the time is right, users should change their passwords for websites they use that may have been compromised. A fairly good list has been published by the folks at Mashable.

If a website or email service provider isn't listed, then you should look on the provider's website for information on Heartbleed for direction, and if none is provided, change your password anyway.

Of course if you rush out and change your password today, before the server vulnerability has been patched, then you run the risk of having to repeat the exercise again once it has been!

Once you've found that a website has been updated with the fix, change your password. Use a different password for each website on which you have an account. This keeps a hacker from potentially getting access to all of the accounts where you used the same password.

Systems administrators have a lot more work to do. The Heartbleed vulnerability may have exposed a lot more than user information and passwords. Not only will OpenSSL libraries need to be updated, but server certificates also will need regenerating, passwords changed and other vulnerable services using TLS updated. This includes services like FTP and VPN and even home network appliances like routers and firewalls most of which use TLS.

Systems Administrators should act quickly to patch all vulnerable systems and test patched systems to ensure that security vulnerabilities do not still exist.

Only then will user confidence be restored and our love relationship with conducting business from the comfort of our homes and workplaces reinstated - albeit more securely than it has been for the past two years!

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