Performing S7comm Protocol Security Analysis

When to Use

• When assessing the security posture of Siemens SIMATIC S7 PLC environments
• When building detection rules for S7comm-based attacks against S7-300/400/1200/1500 controllers
• When performing a security audit of Siemens Step 7/TIA Portal communications
• When investigating suspected unauthorized access to Siemens PLC programs
• When evaluating S7CommPlus integrity mechanisms and their bypass potential

Do not use for scanning production Siemens PLCs without authorization and a test plan (this can crash controllers), for non-Siemens protocol analysis (see detecting-modbus-command-injection-attacks for Modbus), or for modifying PLC programs in a production environment.

Prerequisites

• Network access to the S7comm communication segment (TCP port 102)
• Wireshark with S7comm dissector or Zeek with S7comm protocol analyzer
• Authorized access for security testing (never scan production PLCs without authorization)
• Knowledge of the Siemens PLC models and firmware versions in scope
• Understanding of S7comm protocol structure (COTP, S7 PDU, function codes)