Siemens Nucleus RTOS FTP Server Uncontrolled Resource Consumption (CVE-2022-38371)

high Tenable OT Security Plugin ID 500707

Synopsis

The remote OT asset is affected by a vulnerability.

Description

A vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BACnet) (All versions), APOGEE MEC (PPC) (P2 Ethernet) (All versions), APOGEE PXC Compact (BACnet) (All versions), APOGEE PXC Compact (P2 Ethernet) (All versions), APOGEE PXC Modular (BACnet) (All versions), APOGEE PXC Modular (P2 Ethernet) (All versions), Desigo PXC00-E.D (All versions >= V2.3), Desigo PXC00-U (All versions >= V2.3), Desigo PXC001-E.D (All versions >= V2.3), Desigo PXC100-E.D (All versions >= V2.3), Desigo PXC12-E.D (All versions >= V2.3), Desigo PXC128-U (All versions >= V2.3), Desigo PXC200-E.D (All versions >= V2.3), Desigo PXC22-E.D (All versions >= V2.3), Desigo PXC22.1-E.D (All versions >= V2.3), Desigo PXC36.1-E.D (All versions >= V2.3), Desigo PXC50-E.D (All versions >= V2.3), Desigo PXC64-U (All versions >= V2.3), Desigo PXM20-E (All versions >= V2.3), Nucleus NET (All versions), Nucleus ReadyStart V3 (All versions), Nucleus Source Code (Versions including affected FTP server), TALON TC Compact (BACnet) (All versions), TALON TC Modular (BACnet) (All versions). The FTP server does not properly release memory resources that were reserved for incomplete connection attempts by FTP clients. This could allow a remote attacker to generate a denial of service condition on devices that incorporate a vulnerable version of the FTP server.

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 recommends updating to the latest version of its software where available:

- Nucleus NET: No fix available – users should follow general security measures for mitigation.

- Nucleus ReadyStart V3: Update to V2017.02.4 and apply the patch "2017.02.4_patch_CVE-2022-38371"

- Nucleus Source Code: Contact Siemens (login required) to receive update information

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

- Configure TCP_MAX_KEEPALIVES to a lower value such as 3.
- Configure TCP_KEEPALIVE_INTERVAL and TCP_KEEPALIVE_DELAY be set to 3 seconds.
- Rebuild the application.

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 in HTML or CSAF formats.

Plugin Details

Severity: High

ID: 500707

Version: 1.6

Type: remote

Family: Tenable.ot

Published: 11/7/2022

Updated: 3/4/2024

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2022-38371

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:apogee_modular_building_controller_firmware, cpe:/o:siemens:apogee_modular_equiment_controller_firmware, cpe:/o:siemens:apogee_pxc_compact_firmware, cpe:/o:siemens:apogee_pxc_modular_firmware, cpe:/o:siemens:desigo_pxc00-e.d_firmware, cpe:/o:siemens:desigo_pxc00-u_firmware, cpe:/o:siemens:desigo_pxc001-e.d_firmware, cpe:/o:siemens:desigo_pxc100-e.d_firmware, cpe:/o:siemens:desigo_pxc12-e.d_firmware, cpe:/o:siemens:desigo_pxc128-u_firmware, cpe:/o:siemens:desigo_pxc200-e.d_firmware, cpe:/o:siemens:desigo_pxc22-e.d_firmware, cpe:/o:siemens:desigo_pxc22.1-e.d_firmware, cpe:/o:siemens:desigo_pxc36.1-e.d_firmware, cpe:/o:siemens:desigo_pxc50-e.d_firmware, cpe:/o:siemens:desigo_pxc64-u_firmware, cpe:/o:siemens:desigo_pxm20-e_firmware

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 10/11/2022

Vulnerability Publication Date: 10/11/2022

Reference Information

CVE: CVE-2022-38371

CWE: 401

Detections

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