Modbus/TCP Discrete Input Access

This script is Copyright (C) 2006-2015 Tenable Network Security, Inc.


Synopsis :

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

Description :

Using function code 2, Modbus can read the discrete inputs from a
Modbus slave, which is commonly used by SCADA and DCS field devices.
Discrete inputs represent binary (i.e boolean) values that often map
to switches, relays, or other sensors. A sample of discrete inputs
read from the device are provided by the plugin output.

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: