Modbus/TCP Discrete Input Access

This script is Copyright (C) 2006-2012 Tenable Network Security, Inc.


Synopsis :

Discrete inputs from a Modicon field device such as a PLC, RTU or IED
using Function Code 2 can be read.

Description :

The Modbus protocol function code of 2 reads discrete inputs from
Modbus slave commonly used by SCADA and DCS field devices. Discrete
inputs represent binary (i.e boolean) value that often map to
switches, relays, or other sensors. A sample of discrete inputs read
from the device are provided.

The ability to read discrete inputs may help an attacker profile a
system.

See also :

http://www.modbus.org

Solution :

Restrict access to the Modbus port (TCP 502) to authorized Modbus
clients.

Risk factor :

Medium / CVSS Base Score : 5.0
(CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N)

Family: SCADA

Nessus Plugin ID: 23818 ()

Bugtraq ID:

CVE ID: