The random-number generator on Siemens SIMATIC S7-1200 CPU PLC devices with firmware before 4.0 does not have sufficient entropy, which makes it easier for remote attackers to defeat cryptographic protection mechanisms and hijack sessions via unspecified vectors, a different vulnerability than CVE-2014-2251.
https://cert-portal.siemens.com/productcert/pdf/ssa-654382.pdf
http://www.siemens.com/innovation/pool/de/forschungsfelder/siemens_security_advisory_ssa-654382.pdf