Siemens SIMATIC S7-300 and S7-400 CPUs Insufficiently Protected Credentials (CVE-2020-15791)

medium Tenable OT Security Plugin ID 500385

Synopsis

The remote OT asset is affected by a vulnerability.

Description

A vulnerability has been identified in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions), SIMATIC S7-400 CPU family (incl. SIPLUS variants) (All versions), SIMATIC WinAC RTX (F) 2010 (All versions), SINUMERIK 840D sl (All versions). The authentication protocol between a client and a PLC via port 102/tcp (ISO-TSAP) insufficiently protects the transmitted password. This could allow an attacker that is able to intercept the network traffic to obtain valid PLC credentials.

This plugin only works with Tenable.ot. Please visit https://www.tenable.com/products/tenable-ot for more information.

Solution

The following text was originally created by the Cybersecurity and Infrastructure Security Agency (CISA). The original can be found at CISA.gov.

Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:

- Apply defense-in-depth concepts.
- Apply cell protection concepts.
- For SIMATIC S7-CPU 410 CPUs: Activate field interface security in PCS 7 v9.0, and use a CP443-1 Adv. to communicate with ES/OS

As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for Industrial Security, and following the recommendations in the product manuals.

Follow this link for additional information on Industrial Security by Siemens.

For more information on this vulnerability and the associated mitigations, please see Siemens security advisory SSA-381684

Plugin Details

Severity: Medium

ID: 500385

Version: 1.9

Type: remote

Family: Tenable.ot

Published: 2/7/2022

Updated: 3/4/2024

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Low

Base Score: 3.3

Temporal Score: 2.4

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

CVSS Score Source: CVE-2020-15791

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:siemens:simatic_s7-300_firmware, cpe:/o:siemens:simatic_s7-400_firmware

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 9/9/2020

Vulnerability Publication Date: 9/9/2020

Reference Information

CVE: CVE-2020-15791

CWE: 522

Detections

Analytics