MODBUS/TCP 'Force Listen Mode' Function Code Detection (SCADA)

info Nessus Network Monitor Plugin ID 41

Description

The MODBUS/TCP client has sent a MODBUS server a Force Listen Mode request. The Force Listen Mode request, function code 8 (0x08) and subfunction code 4 (0x04), will cause the target server into listen-only mode; i.e., it will not send any responses. This function is typically implemented only in serial devices.

Plugin Details

Severity: Info

ID: 41

Family: SCADA