webvrpcs.exe in Advantech/BroadWin WebAccess allows remote attackers to execute arbitrary code or obtain a security-code value via a long string in an RPC request to TCP port 4592.
http://www.us-cert.gov/control_systems/pdf/ICSA-11-094-02A.pdf
http://www.us-cert.gov/control_systems/pdf/ICS-ALERT-11-081-01.pdf
http://www.securityfocus.com/archive/1/517117
http://www.reversemode.com/downloads/Scada_Trojans_Ruben_Rootedcon.pdf