SCADA Hackers Go On Defense

MIAMI, FL -- S4 Conference -- One of the most prolific SCADA bug-finding research teams is building a prototype defensive technique for protecting industrial control systems they are best known for hacking.

Luigi Auriemma and Donato Ferrante of Malta-based ReVuln here yesterday gave a peek at their latest project, called SCADA Shield. "We are talking about defense today, which is pretty odd" for us, Ferrante said.

The researchers also announced that they are now officially offering to their own customers custom patches for SCADA systems that can be used in lieu of patches from the vendors. Auriemma and Ferrante said their patches are not one-off fixes like a vendor's patch would be. They don't just patch for a buffer overflow flaw in SCADA software, for example, but the underlying software code that causes those types of bugs. "We patch for the root cause of the problem," Auriemma said.

This is a memory-based patch that can be applied without powering down the system, they said. The patch also blocks attacks exploiting zero-day bugs found by ReVuln and allows for runtime patching -- something that traditional patching typically doesn't support.

Only about 10 to 20 percent of organizations today actually install the patches that their SCADA vendors are releasing, according to SCADA security experts.

[Industrial control systems vendors are starting to patch security bugs, but actually installing the fixes can invite more trouble. See The SCADA Patch Problem.]

"SCADA software must remain up all the time. To stop and apply a patch isn't OK. You want an alternative, to be able to patch in runtime in memory," ReVuln's Auriemma said.

But an in-memory fix is not a new concept, noted Roel Schouwenberg, senior researcher for global research and analysis at Kaspersky Lab.

Is it better than not patching at all? "I'm not really sure. I think it's a really hard sell because it takes awhile to patch stuff [in ICS] because you need to go through [thorough] testing," Schouwenberg said. "If you talk about risk management strategies, there are obvious advantages to in-memory patching: You don't need to restart the service. But it also brings with it extra risks of instability and so on."

Whether customers will be comfortable applying a patch from a third party rather than installing one from their vendor remains to be seen. Ralph Langner of Langner Communications said it's unclear which organizations would be willing to apply a patch that didn't come from their vendor.

"Most of the [SCADA] vendors are in the process of building new products," he said. "They don't have security built in [now]. But at some point in time, we will see it as one of the biggest priorities."

Said Dale Peterson, CEO of Digital Bond, of whether ReVuln's custom-patch strategy will catch on: "In the end, the market will speak."

ReVuln's SCADA-Shield prototype, meanwhile, works with both new as well as older versions of Windows that haunt ICS environments, such as Windows 98. It detects exploit attempts using the company's "smart engine" that doesn't require signatures.

"We wanted to write a software solution to protect SCADA/HMI products. It's a sort of shield you can apply to them," Ferrante said. "If you want a good chance to detect most of security vulnerabilities, like buffer overflows, directory traversal, and all of that stuff," it's another layer of security, he said.

The goal is to mitigate entire classes of vulnerabilities -- buffer overflow, directory traversal, injections -- while keeping the SCADA service on, he said. "We want to avoid false positives" as well, he said.

SCADA-Shield is still in the early stages of development and its current features are just a subset of the final version. Auriemma said ReVuln has not yet set a time frame for its release.

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