Siemens SIMATIC and SCALANCE Devices Use After Free (CVE-2023-4623)

high Tenable OT Security Plugin ID 502897

Synopsis

The remote OT asset is affected by a vulnerability.

Description

A use-after-free vulnerability in the Linux kernel's net/sched:
sch_hfsc (HFSC qdisc traffic control) component can be exploited to achieve local privilege escalation. If a class with a link-sharing curve (i.e. with the HFSC_FSC flag set) has a parent without a link- sharing curve, then init_vf() will call vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling pointer that can cause a use-after-free. We recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f.

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 risk:

- All affected products: Update to V3.0.0 or later version

As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. To operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens' operational guidelines for industrial security and following recommendations in the product manuals.

Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage

For more information see the associated Siemens security advisory SSA-769027 in HTML and CSAF.

Plugin Details

Severity: High

ID: 502897

File Name: tenable_ot_siemens_CVE-2023-4623.nasl

Version: 1.5

Type: remote

Family: Tenable.ot

Published: 2/24/2025

Updated: 2/14/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2023-4623

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

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

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

Vulnerability Information

CPE: cpe:/o:siemens:scalance_wam763-1_%28us%29_firmware:3.0.0, cpe:/o:siemens:scalance_wam763-1_firmware:3.0.0, cpe:/o:siemens:scalance_wam766-1_%28us%29_firmware:3.0.0, cpe:/o:siemens:scalance_wam766-1_%28me%29_firmware:3.0.0, cpe:/o:siemens:scalance_wum763-1_firmware:3.0.0, cpe:/o:siemens:scalance_wub762-1_ifeatures_firmware:3.0.0, cpe:/o:siemens:scalance_wam766-1_firmware:3.0.0, cpe:/o:siemens:scalance_wam766-1_eec_%28us%29_firmware:3.0.0, cpe:/o:siemens:scalance_wum766-1_firmware:3.0.0, cpe:/o:siemens:scalance_wam766-1_eec_%28me%29_firmware:3.0.0, cpe:/o:siemens:simatic_s7-1500_cpu_firmware:3.1.5, cpe:/o:siemens:scalance_wab762-1_firmware:3.0.0, cpe:/o:siemens:scalance_wam766-1_eec_firmware:3.0.0, cpe:/o:siemens:scalance_wub762-1_firmware:3.0.0, cpe:/o:siemens:scalance_wam763-1_%28me%29_firmware:3.0.0, cpe:/o:siemens:simatic_s7-1500_tm_mfp, cpe:/o:siemens:scalance_wum766-1_%28usa%29_firmware:3.0.0, cpe:/o:siemens:scalance_wum766-1_%28me%29_firmware:3.0.0, cpe:/o:siemens:siplus_s7-1500_cpu_firmware:3.1.5, cpe:/o:siemens:scalance_wum763-1_%28us%29_firmware:3.0.0

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 6/13/2023

Vulnerability Publication Date: 6/13/2023

Reference Information

CVE: CVE-2023-4623

CWE: 416

ICSA: 25-044-09

Detections

Analytics