LOGO! CMR family is a communication system suitable for monitoring distributed devices and systems via text messages or e-mail. siemens SIMATIC RTU3000C is a compact RTU from Siemens (Germany) is an energy self-sufficient low-power remote terminal unit (RTU). siemens LOGO! CMR family and SIMATIC RTU 3000 family security feature issue vulnerability, the vulnerability stems from the product underlying TCP IP stack does not correctly calculate the random number used as the ISN (initial sequence number). An attacker could exploit the vulnerability by jamming traffic, spoofing connections and gaining access to sensitive information.