ICS / OTTCP 102 Cleartext by default
Port 102: S7comm
Siemens S7 (ISO-TSAP)
The protocol used by many Siemens PLCs, carried over ISO-TSAP on port 102.
How attackers abuse it
- Unauthorised program upload and download to PLCs - the mechanism Stuxnet exploited.
How to defend it
- Segmentation, PLC protection levels and passwords, and monitoring of program changes.
Exam tip
Stuxnet altered PLC logic while showing operators normal values - integrity of control logic matters.