Efforts to strengthen critical infrastructure targets continue to focus on front-end systems rather than on underlying industrial control systems where the real problems exist, security experts warned this week.
The Stuxnet worm that last year showed how flaws in control systems can be exploited to cause damage to physical assets, but it hasn't yet led to significant security upgrades, they contended.
"Everyone keeps focusing on PCs while PLCs (programmable logic controllers) are still in the same state they were 10 years ago," said Dale Peterson, CEO of Digital Bond, a consulting firm specialising in control system security.
The issue has been longstanding within the industrial control system (ICS) community and surfaced again this week with the release of a Symantec report that the new Duqu Trojan has links to Stuxnet.
According to Symantec, the Duqu worm appears have been built to steal critical information from vendors of industrial control systems.
Unlike Stuxnet, Duqu does not directly target industrial control systems though information it gathers could be used to create the next Stuxnet, Symantec warned.
The report reignited fears about cyberattacks targeted at the control systems behind equipment at critical infrastructure such as power plants, water treatment facilities and chemical plants.
Most flaws are at the engineering workstation layer
The problem, though, is that the concerns so far have focused on the front-end, mostly Windows-based Human Machine Interface (HMI) systems that are used to interact with control systems, Peterson said.
Many flaws that have been described as control systems flaws have really been at the front-end engineering workstation layer.
For example last month, Italian researcher Luigi Auriemma disclosed several zero-day vulnerabilities in Supervisory Control and Data Acquisition (SCADA) products from multiple vendors including Rockwell Automation, Cogent Datahub, Measuresoft and Progea.
Earlier this year, Auriemma had disclosed similar flaws in products from Siemens, Iconics, 7-Technologies and Datac. Most of the flaws were at the HMI layer.
"There are vulnerabilities in all components but HMI [flaws] are the easiest for researchers to get their hands on," Peterson said.
While addressing such flaws is vital, it is equally important to address flaws in the control systems themselves, said Joseph Weiss, managing partner at Applied Control Systems LLC and author of the book Protecting Industrial Control Systems from Electronic Threat. "These are the flaws that can cause things to go boom at night."
"If you haven't protected HMI's, shame on you," Weiss said. But the bigger threats really are the control system flaws that allow attackers to send commands that cause physical equipment to shut down, overheat or blow-up, he added.
There is no security around commands to turn things off
Stuxnet showed how programmable logic controllers could be overwritten to send commands that caused equipment to fail, he said. Despite that warning, little has changed. "Prior to Stuxnet there were zero programs for securing PLCs. To this day there are no programs for securing PLCs," Weiss said.
A lot of the problems have to do with insecure design, Peterson said.
For example, in many cases anyone with logical access to a control system can upload firmware on it without authentication, he said. Passwords are often hardcoded into systems many have administrative backdoors, and very basic buffer overflow errors.
Often, "there is no security around write commands or turning things on and off, or changing a process. You want some control over what happens," Peterson said.
The problem is not an easy one to fix, Peterson added.
Major control systems do not get replaced for years. And even if they were replaced, the replacement systems are likely to be as vulnerable as their predecessors, he said.
"The real shame is that most vendors don't even have a secure system you can buy today. It's a problem that has had little progress," Peterson said.
According to Weiss, the real focus has to be on coming up with a contingency plan in the event of an attack. Many deficiencies in control systems cannot be patched, he said. "There is no antivirus for it," he said. So the focus now has to be on resilience and recovery, he said.