Modbus/TCP Discrete Input Access

medium Nessus Plugin ID 23818

Language:

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.

Solution

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

Plugin Details

Severity: Medium

ID: 23818

File Name: scada_modbus_di_check.nbin

Version: 1.66

Type: remote

Family: SCADA

Published: 12/11/2006

Updated: 7/17/2024

Supported Sensors: Nessus

Risk Information

CVSS Score Rationale: Manually scored based on the nature of the vulnerability.

CVSS v2

Risk Factor: Medium

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N

CVSS Score Source: manual

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS Score Source: manual

Vulnerability Information

Required KB Items: SCADA/modbus/coil

Detections

Analytics