Some Thoughts on Security
With the recent Heartbleed security exploit in the OpenSSL library a lot of attention has been focused on how vulnerable our computer systems have become to data theft. With so much data travelling the Internet as well as travelling wireless networks, this has brought home the importance of how secure these systems are. With a general direction towards an Internet of Things this makes all our devices whether our fridge or our car possibly susceptible to hackers.
I’ll talk about Heartbleed a bit later, but first perhaps a bit of history with my experiences with secure computing environments.
My last co-op work term was at DRDC Atlantic in Dartmouth, Nova Scotia. In order to maintain security they had a special mainframe for handling classified data and to perform classified processing. This computer was located inside a bank vault along with all its disk drives and tape units. It was only turned on after the door was sealed and it was completely cut off from the outside world. Technicians were responsible for monitoring the vault from the outside to ensure that there was absolutely no leakage of RF radiation when classified processing was in progress.
After graduation from University my first job was with Epic Data. One of the projects I worked on was a security system for a General Dynamics fighter aircraft design facility. This entire building was built as a giant Faraday cage. The entrances weren’t sealed, but you had to travel through a twisty corridor to enter the building to ensure there was not line for radio waves to pass out. Then surrounding the building was a large protected parking lot where only authorized cars were allowed in.
Generally these facilities didn’t believe you could secure connections with the outside world. If such a connection existed, no matter how good the encryption and security measures, a hacker could penetrate it. The hackers they were worried about weren’t just bored teenagers living in their parent’s basements, but well trained and financed hackers working for foreign governments. Something like the Russian or Chinese version of the NSA.
Van Eck Phreaking
A lot of attention goes to securing Internet connections. But historically data has been stolen through other means. Van Eck Phreaking is a technique to listen to the RF radiation from a CRT or LCD monitor and to reconstruct the image from that radiation. Using this sort of technique a van parked on the street with sensitive antenna equipment can reconstruct what is being viewed on your monitor. This is even though you are using a wired connection from your computer to the monitor. In this case how updated your software is or how secure your cryptography is just doesn’t matter.
Everything is Wireless
It seems that every now and then politicians forget that cell phones are really just radios and that anyone with the right sort of radio receiver can listen in. This seems to lead to a scandal in BC politics every couple of years. This is really just a reminder that unless something is specifically marked as using some sort of secure connection or cryptography, it probably doesn’t. And then if it doesn’t anyone can listen in.
It might seem that most communications are secure now a days. Even Google search switches to always use https which is a very secure encrypted channel to keep all your search terms a secret between yourself and Google.
But think about all the other communication channels going on. If you use a wireless mouse or a wireless keyboard, then these are really just short range radios. Is this communications encrypted and secure? Similarly if you use a wireless monitor, then it’s even easier to eavesdrop on than using Van Eck.
What about your Wi-Fi network? Is that secure? Or is all non-https traffic easy to eavesdrop on? People are getting better and better at hacking into Wi-Fi networks.
In your car if you are using your cell phone via blue tooth, is this another place where eavesdropping can occur?
Heartbleed is an interesting bug in the OpenSSL library that’s caused a lot of concern recently. The following XKCD cartoon gives a good explanation of how a bug in validating an input parameter caused the problem of leaking a lot of data to the web.
At the first level, any program that receives input from untrusted sources (i.e. random people out on the Internet) should very carefully and thoroughly valid any input. Here you can tell it what to reply and the length of the reply. If you give a length much longer than what was given then it leaks whatever random contents of memory were located here.
At the second level, this is an API design flaw, that there should never have been such a function with such parameters that could be abused thus.
At the third level, what allows this to go bad is a performance optimization that was put in the OpenSSL library to provide faster buffer management. Before this performance enhancement, this bug would just have caused an application fault. This would have been bad, but been easy to detect and wouldn’t have leaked any data. At worst it would have perhaps allowed some short lived denial of service attacks.
Mostly exploiting this security hole just returns the attacker with a bunch of random garbage. The trick is to automate the attack to repeatedly try it on thousands of places until by fluke you find something valuable, perhaps a private digital key or perhaps a password.
The open source community makes the claim that open source code is safer because anyone can review the source code and find bugs. So people are invited to do this to OpenSSL. I think Heartbleed shows that security researcher became complacent and weren’t examining this code closely enough.
The code that caused the bug was checked in by a trusted coder, and was code reviewed by someone knowledgeable. Mistakes happen, but for something like this, perhaps there was a bit too much trust. I think it was an honest mistake and not deliberate sabotage by hackers or the NSA. The source code change logs give a pretty good audit of what happened and why.
Should I Panic?
In spite of what some reporters are saying, this isn’t the worst security problem that has surfaced. The holy grail of hackers is to find a way to root computers (take them over with full administrator privileges). This attack just has a small chance of providing something to help on this way and isn’t a full exploit in its own right. Bugs in Java, IE, SQL Server and Flash have all allowed hackers to take over peoples computers. Some didn’t require anything else, some just required tricking the user into browsing a bad web site. Similarly e-mail or flash drive viruses have caused far more havoc than this particular problem. Another really on-going security weakness is caused by government regulations restricting the strength of encryption or forcing the disclosure of keys, these measures do little to help the government, but they really make the lives of hackers easier. I also think that e-mail borne viruses have wreaked much more havoc than Heartbleed is likely to. But I suspect the biggest source of identity theft is from data recovered from stolen laptops and other devices.
Another aspect is the idea that we should be like gazelle’s and rely on the herd to protect us. If we are in a herd of 100 and a lion comes along to eat one of us then there is only a 1/1000 chance that it will be me.
This attack does highlight the importance of some good security practices. Such as changing important passwords regularly (every few months) and using sufficiently complex or long passwords.
All that being said, nearly every website makes you sign in. For web sites that I don’t care about I just use a simple password and if someone discovers it, I don’t really care. For other sites like personal banking I take much more care. For sites like Facebook I take medium care. Generally don’t provide accurate personal information to sites that don’t need it, if they insist on your birthday, enter it a few days off, if they want a phone number then make one up. That way if the site is compromised then they just get a bunch of inaccurate data on you. Most sites ask way too many things. Resist answering these or answer them inaccurately. Also avoid overly nosey surveys, they may be private and anonymous, unless hacked.
The good thing about this exploit, seems to be that it was discovered and fixed mostly before it could be exploited. I haven’t seen real cases of damage being done. Some sites (like the Canadian Revenue Services) are trying to blame Heartbleed for unrelated security lapses.
Generally the problems that you hear about are the ones that you don’t need to worry so much about. But again it is a safe practice to use this as a reminder to change your passwords and minimize the amount of personally identifiable data out there. After all dealing with things like identity theft can be pretty annoying. And this also help with the problems that the black hat hackers know about and are using, but haven’t been discovered yet.
You always need to be vigilant about security. However it doesn’t help to be overly paranoid. Follow good on-line practices and you should be fine. The diversity of computer systems out there helps, not all are affected and those that are, are good about notifying those that have been affected. Generally a little paranoia and good sense can go a long way on-line.