Siemens SIMATIC HMI Comfort Panels before WinCC (TIA Portal) 13 SP1 Upd2 and SIMATIC WinCC Runtime Advanced before WinCC (TIA Portal) 13 SP1 Upd2 allow man-in-the-middle attackers to cause a denial of service via crafted packets on TCP port 102.
https://cert-portal.siemens.com/productcert/pdf/ssa-487246.pdf
http://www.siemens.com/innovation/pool/de/forschungsfelder/siemens_security_advisory_ssa-487246.pdf