A vulnerability has been identified in Firmware variant PROFINET IO for EN100 Ethernet module : All versions < V1.04.01; Firmware variant Modbus TCP for EN100 Ethernet module : All versions < V1.11.00; Firmware variant DNP3 TCP for EN100 Ethernet module : All versions < V1.03; Firmware variant IEC 104 for EN100 Ethernet module : All versions < V1.21; EN100 Ethernet module included in SIPROTEC Merging Unit 6MU80 : All versions < 1.02.02. The integrated web server (port 80/tcp) of the affected devices could allow remote attackers to obtain a limited amount of device memory content if network access was obtained. This vulnerability only affects EN100 Ethernet module included in SIPROTEC4 and SIPROTEC Compact devices.
https://www.siemens.com/cert/pool/cert/siemens_security_advisory_SSA-323211.pdf
https://ics-cert.us-cert.gov/advisories/ICSA-17-187-03
https://ics-cert.us-cert.gov/advisories/ICSA-16-140-02
http://www.siemens.com/cert/pool/cert/siemens_security_advisory_ssa-547990.pdf