Security researchers pull talk on security vulnerabilities in Siemens PLC systems. Siemens and U.S. Department of Homeland Security pointed out scope of the problem, NSS Labs CEO says. The company had been working with DHS’s ICS CERT (Industrial Control Systems Cyber Emergency Response) group for the past week-and-a-half trying to get the issue resolved. “We felt it would be potentially very negative to the public if information was put out without mitigation being available,” he says.”]