Siemens SIMATIC WinCC before 7.3, as used in PCS7 and other products, allows local users to gain privileges by leveraging weak system-object access control.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2014-4604
http://www.siemens.com/innovation/pool/de/forschungsfelder/siemens_security_advisory_ssa-214365.pdf