This week I have been present at SANS ICS Security Amsterdam, taking one of their courses on security for industrial control systems. This has been a fantastic opportunity to learn new things, reinforce known concepts at a deeper level, and to network and meet with a large range of people with interests in this field. I’ve been surprised to see people from law enforcement, national security, industry representatives, consultants and vendors coming together at one event. Information security has been a lot in the news lately, and is seen as a big part of the risk picture in almost every region and every industry.
Two things in particular have been very interesting to see when it comes to the stuff presented by the SANS course instructors:
- Security researchers continue to find basic vulnerabilities in new product lines from major vendors (the big companies we’ve all heard about, I’m not going to shame anyone)
- A lot of control systems are still facing the internet, are directly accessible with no or very weak security, and attacks are prevalent as found in honeypot research experiments
Basically, this confirms the notion that “the situation is bad and we need to do something about it”. People said this after Stuxnet, and they are still saying it. My impression from working with various clients is that industry is aware of the risks that exist “out there” but they are in varying degree doing something to control that risk. Too many still believe that “we will never be compromised as long as we have a firewall”. Relating to this, one might ask, what are the “basic vulnerabilities” and how do we work around that?
Many control system components today run on commodity OS’s, or are connected to servers running MS Windows or Linux, e.g. used to display HMI’s. These HMI’s are in many modern systems developed as web apps (running on local servers) for portability, ease of access, etc. This means that many of the vulnerabilities found in regular IT and on the web also apply to control systems. However, these risks are worse in the control system world because these systems need to run all the time and can therefore often not be patched, and should someone break in, they could cause real physical damage (think crashing of cars, blowing up an oil rig or destroying a melting furnace). Some of the top vulnerabilities we are exposed to are the following: buffer overflows (yes, still, lots of stuff running on old systems), SQL injection vulnerabilities and cross-site scripting vulnerabilities (web interfaces…). So, if we cannot patch, what can we do about this?
First of all, perform a risk and vulnerability assessment, taking both possible scenarios and credibility of scenarios into account. Make sure to establish a good baseline security policy and use this for managing these issues – there is lots of guidance available, and often sector specific. If you cannot patch, focus on what you can do; ensure everyone involved in purchasing, maintaining, producing and using control systems are aware of the risks and what types of behaviors are good, and what types are bad. This means that security awareness must be built into the organizational culture.
On the technical side, maybe especially with lots of legacy systems running, make sure the network architecture is reasonable and safe – avoid having critical assets directly facing the internet (do a Shodan search and you will find that lots of asset owners are not following good practice here). The architecture must weight risks and business needs – a full lockdown may be the safest way to go, but it may also stop core business functions from working.
Further, should a breach occur, make sure you have the organizational and technical capabilities to deal with that. Plan and train on incident response – and remember you are not alone. Get help from vendors both in managing the assets during normal operations, and during a crisis situation. Including incident response in service agreements may thus be a good idea.
This was a quick summary of topics we’ve looked at during training, and discussed over beers in Amsterdam. The training by SANS has been excellent, and I’m looking forward to bringing reinforced and new insights back to the office on Monday.