Siemens S7-400 CPUs Improper Input Validation (CVE-2018-16556)

high Tenable OT Security Plugin ID 500284

Synopsis

The remote OT asset is affected by a vulnerability.

Description

A vulnerability has been identified in SIMATIC S7-400 (incl. F) V6 and below (All versions), SIMATIC S7-400 PN/DP V7 (incl. F) (All versions), SIMATIC S7-400H V4.5 and below (All versions), SIMATIC S7-400H V6 (All versions < V6.0.9), SIMATIC S7-410 (All versions < V8.2.1). Specially crafted packets sent to port 102/tcp via Ethernet interface, via PROFIBUS, or via Multi Point Interfaces (MPI) could cause the affected devices to go into defect mode. Manual reboot is required to resume normal operation. Successful exploitation requires an attacker to be able to send specially crafted packets to port 102/tcp via Ethernet interface, via PROFIBUS or Multi Point Interfaces (MPI). No user interaction and no user privileges are required to exploit the security vulnerability. The vulnerability could allow causing a Denial-of- Service condition of the core functionality of the CPU, compromising the availability of the system. At the time of advisory publication no public exploitation of this security vulnerability was known.

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 implementing the following mitigations:

- Configure protection Level 3 (read/write protection) to mitigate CVE-2018-16557
- Restrict network access to affected devices; restrict network access to Port 102/TCP for Ethernet interfaces.
- For SIMATIC S7-CPU 410 CPUs: Activate field interface security in PCS 7 v9.0, use a SIMATIC CP443-1 Adv. to communicate with ES/OS, and update to Version 8.2.1:

https://support.industry.siemens.com/cs/ww/en/view/109476571

- For SIMATIC S7-400H V6: Update to Version 6.0.9

https://support.industry.siemens.com/cs/ww/en/view/109474550

- Apply defense-in-depth:

https://www.siemens.com/cert/operational-guidelines-industrial-security

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 (download:
https://www.siemens.com/cert/operational-guidelines-industrial-security), and following the recommendations in the product manuals.

For more information on these vulnerabilities and associated software updates, please see Siemens security advisory SSA-113131 on their website:

https://www.siemens.com/cert/advisories

Plugin Details

Severity: High

ID: 500284

Version: 1.7

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: 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-2018-16556

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:simatic_s7-400h_firmware, cpe:/o:siemens:simatic_s7-400h_v6_firmware, cpe:/o:siemens:simatic_s7-400_pn%2fdp_v6_firmware, cpe:/o:siemens:simatic_s7-400_pn%2fdp_v7_firmware

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 12/13/2018

Vulnerability Publication Date: 12/13/2018

Reference Information

CVE: CVE-2018-16556

CWE: 20

Detections

Analytics