Siemens SIMATIC WinCC OA before 3.12 P002 January uses a weak hash algorithm for passwords, which makes it easier for remote attackers to obtain access via a brute-force attack.
https://exchange.xforce.ibmcloud.com/vulnerabilities/90934
http://www.siemens.com/innovation/pool/de/forschungsfelder/siemens_security_advisory_ssa-342587.pdf