SCADA Security In A Post-Stuxnet World

New data points illustrate just what a turning point Stuxnet truly was in SCADA security: Twenty times more software flaws have been discovered in industrial-control systems (ICS)/SCADA systems since the 2010 discovery of Stuxnet, and the vendor whose PLC system was its ultimate target has patched 92 percent of reported vulnerabilities in its products over the past seven years.

New data from Positive Technologies Security finds that 64 vulnerabilities were discovered and reported in industrial-control system products by the end of 2011, while only nine were reported between 2005 and 2011. And between January and August of this year, some 98 bugs were reported.

The Russian researchers who authored the report based their data on vulnerability database information from ICS-CERT, CVE, Bugtraq, NVD, OSVDB, Mitre Oval Repositories, exploit-db, and Siemens Product CERT, as well as from exploit packs from Metasploit and Immunity, for instance.

"The history of industrial system security is divided into two parts — prior to Stuxnet and afterwards," the authors wrote. "20 times more vulnerabilities have been detected since 2010 comparing with the previous five years."

Some 35 percent of reported vulnerabilities also have exploits, and about half of the vulnerabilities could allow an attacker to execute code remotely. More than 40 percent of the bugs are considered "critical," according to the "SCADA Safety In Numbers" report.

But in reality, the 35 percent number is likely higher, says Dale Peterson, CEO of Digital Bond. "I would have thought it was higher than 35 percent," especially given how penetration testing tools like Metasploit and others typically convert vulnerabilities into exploits regularly, he says.

"What you don't see in [Positive Technologies'] numbers is that a tremendous amount of exploits are not disclosed. They are known or covered by NDA, or whoever found them feels they should not be disclosed," Peterson says. He estimates less than one-fourth of the vulnerabilities his firm finds can actually be publicly disclosed because they are found as part of a consulting engagement and are under NDAs.

Meanwhile, Siemens, whose Siemens S7 PLC was in the bull's eye of the Stuxnet attack, had twice as many bugs reported in its products, but the researchers attribute much of that to the SCADA vendor becoming more proactive in rooting out flaws in its code. Siemens established its own Computer Emergency Response Team in the wake of Stuxnet that has helped spot and fix flaws. "The vulnerabilities discovered by the team are also included in the general statistics; thus the number of discovered and fixed issues is increasing," the researchers wrote.

And the popularity of Siemens products is a big factor, says Sergey Gordeychik, a Positive Technologies researcher and co-author of the report. "The main reason is popularity of Siemens solutions. During our marketing research, we found ... Siemens products on one- to four places in clients' requests. Other popular vendors -- Wonderware, Emmerson -- don't have such huge installation base," Gordeychik says.

Digital Bond's Peterson says Siemens and other SCADA vendors have made inroads in better securing server and workstation components. "They certainly have improved in their handling of vulnerabilities," he says. "When something becomes public, it tends to get fixed."

According to Positive Technologies, Siemens patched around 90 percent of its vulnerabilities; Advantech/Broadwin, 91 percent; WellInTech, 89 percent; General Electric, 80 percent; Rockwell Automation, 78 percent; ABB, 67 percent; and Schneider Electric, 56 percent.

More than 80 percent of the bugs were fixed within 30 days of public disclosure -- a rate that the researchers call relatively efficient. But every fifth bug was either not fixed at all or fixed "with a significant delay."

But ferreting out security vulnerabilities in traditional SCADA products that weren't created under a security development life cycle program is a never-ending process. "[It's] almost a losing battle because you find one and patch it ... but there are systemic problems in the product," Peterson says. "It's just going to be a never-ending flow of vulnerabilities until you actually go in and redesign that code. That's what a lot of these vendors are facing: It's like a bucket with a bunch of holes in it that's rusting out. You just need to start over."

[Itron, which sells smart meters, data collection, and software solutions to around 8,000 utilities in more than 130 countries and regions worldwide, has made SDL mandatory in all hardware and software development. See SCADA/Smart-Grid Vendor Adopts Microsoft's Secure Software Development Program .]

Peterson says some vendors like Siemens have made progress on the workstation and server side, incorporating good security controls. But the PLC side has made "very little progress," he says.

What does the report say about the overall security of the world's critical infrastructure?

What does the report say about the overall security posture of critical infrastructure systems? "In general, the results [were] predicable. ICS security now looks like Internet security in early 2000, and we can compare Stuxnet with CodeRed/Nimda worms. It's like a trigger," Positive Technologies' Gordeychik says.

The full Positive Technologies report is available here (PDF) for download.

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