Siemens LOGO! CMR and SIMATIC RTU 3000 Incorrect Calculation of Buffer Size (CVE-2020-36475)

high Tenable OT Security Plugin ID 501676

Synopsis

The remote OT asset is affected by a vulnerability.

Description

An issue was discovered in Mbed TLS before 2.25.0 (and before 2.16.9 LTS and before 2.7.18 LTS). The calculations performed by mbedtls_mpi_exp_mod are not limited; thus, supplying overly large parameters could lead to denial of service when generating Diffie- Hellman key pairs.

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.

For LOGO! CMR2020, Siemens recommends affected users update to v2.2 or later. For LOGO! CMR2040, Siemens recommends affected users update to v2.2 or later.

For the SIMATIC RTU 3000 family, Siemens recommends affected users use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. Refer to the product manual for further information.

Plugin Details

Severity: High

ID: 501676

Version: 1.2

Type: remote

Family: Tenable.ot

Published: 9/21/2023

Updated: 12/19/2023

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

CVSS Score Source: CVE-2020-36475

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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

Vulnerability Information

CPE: cpe:/o:siemens:logo%21_cmr2020_firmware, cpe:/o:siemens:logo%21_cmr2040_firmware

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 8/23/2021

Vulnerability Publication Date: 8/23/2021

Reference Information

CVE: CVE-2020-36475

CWE: 131

Detections

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