Siemens InsydeH2O SMM Privilege Escalation (CVE-2020-5953)

high Tenable OT Security Plugin ID 501734

Synopsis

The remote OT asset is affected by a vulnerability.

Description

A vulnerability exists in System Management Interrupt (SWSMI) handler of InsydeH2O UEFI Firmware code located in SWSMI handler that dereferences gRT (EFI_RUNTIME_SERVICES) pointer to call a GetVariable service, which is located outside of SMRAM. This can result in code execution in SMM (escalating privilege from ring 0 to ring -2).

Insyde BIOS is typically used in RUGGEDCOM APE products and some SIMATIC devices. Please refer to the vendor advisory for a precise list of models concerned.

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

Solution

Refer to the vendor advisory.

Plugin Details

Severity: High

ID: 501734

Version: 1.1

Type: remote

Family: Tenable.ot

Published: 9/26/2023

Updated: 9/27/2023

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: High

Score: 7.3

CVSS v2

Risk Factor: Medium

Base Score: 6.9

Temporal Score: 5.1

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

CVSS Score Source: CVE-2020-5953

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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

Vulnerability Information

CPE: cpe:/a:insyde:insydeh2o:5.12.09.0074, cpe:/a:insyde:insydeh2o:5.23.04.0045, cpe:/a:insyde:insydeh2o:5.23.45.0023, cpe:/a:insyde:insydeh2o:5.33.15.0034, cpe:/a:insyde:insydeh2o:5.34.03.0029, cpe:/a:insyde:insydeh2o:5.42.03.0010

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 2/3/2022

Vulnerability Publication Date: 2/3/2022

Reference Information

CVE: CVE-2020-5953

Detections

Analytics