The company issued a statement today indicating that the flaws recently discovered and reported to it by Dillon Beresford of NSS Labs aren't a physical danger as was indicated initially. "Independent research uncovered that the Siemens PLCs (Programmable Logic Controllers) entered into a secure stop mode when the gap was tested without any IT security measures. In this environment, the PLC would have stopped a manufacturing process in a controlled manner. For customers with standard IT security measures in place, there is no risk for workers or the manufacturing process," the company said in a statement in response to a press request for an interview.
But the fact that a plant floor system, such as a cooling system for a boiler,actually grinds to a halt is still unsafe, notes HD Moore, chief security officer for Rapid7 and creator of Metasploit. "There's no safe way to stop a boiler [cooling system]. This downplays the fact that a device that's keeping something safe ... still stops," he says.
Moore is currently working on modules for the Metasploit penetration-testing tool that would provide pen testers with exploits for the flaws in the Siemens products. He's under embargo and unable to discuss details of the flaws discovered by Beresford, who wrote Metasploit modules for his proof-of-concept and shared them with Moore.
Moore says these types of attacks could also extend to other vendors' SCADA systems, as well.
Patching Siemens' systems ultimately might not solve much. Moore says few users are likely to deploy the firmware updates. "It doesn't make sense to install these updates," Moore says. Patching SCADA systems isn't as simple as taking them down and slapping on the patch, and the devices are already very fragile to disruption, he says. Under NERC regulations, for example, any firmware updates require proper testing before going live. "These [systems] are more difficult to upgrade. You can't just pull them offline and then put them back up," Moore notes.
Even so, Moore confirmed Siemens' stipulation that a tight IT security setup, including a locked-down firewall and no wireless, for example, should protect plants from attacks exploiting these flaws. But, in the end, it really depends on the overall environment, he says. "If you have 3,000 unprotected oil wells on the network, it won't help much," he notes.
Rick Moy, president of NSS Labs, says his firm will demonstrate the attacks to ICS operators in its Austin, Texas, laboratory on June 2. NSS Labs is accepting applications for registration here.
NSS Labs' Beresford canceled his talk at TakedownCon 2011 in Dallas at the eleventh hour last week due to concerns about the content's possible risk to human life. He had planned to reveal vulnerabilities and proof-of-concept (PoC) exploit code for flaws in Siemens SCADA industrial-control systems products.
Meanwhile, Siemens today said it's "in direct contact with its customers on a regular basis with regard to security gaps identified in its products," that it has already built the updates for its PLCs, and is currently testing them in-house in "joint cooperation with ICS-CERT."
"We anticipate having these updates available for our customers within the next few weeks. Ongoing communication will be available at www.siemens.com/industrialsecurity," according to the company. Have a comment on this story? Please click "Add Your Comment" below. If you'd like to contact Dark Reading's editors directly, send us a message.