1. EXECUTIVE SUMMARY

  • CVSS v3 7.8
  • ATTENTION: Low skill level to exploit
  • Vendor: Siemens
  • Equipment: TIA Portal and PCS neo
  • Vulnerability: Improper Access Control

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow local users to escalate privileges and execute code as a local SYSTEM user.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following Siemens products, are affected:

  • PCS neo (Administration Console): v3.0
  • TIA Portal: v15, v15.1, and v16

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER ACCESS CONTROL CWE-284

The affected product has improper access controls, which may allow an attacker to execute code with SYSTEM privileges. 

CVE-2020-25238 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

3.3 BACKGROUND

  • CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
  • COUNTRIES/AREAS DEPLOYED: Worldwide
  • COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Will Dormann from CERT Coordination Center (CERT/CC) reported this vulnerability to Siemens.

4. MITIGATIONS

Siemens has released the following update and recommends it be applied:

Tia Portal: Update TIA Administrator to v1.0 SP2 Upd2 or later version

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

As a general security measure, Siemens strongly recommends users protect network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends users configure the environment according to Siemens’ operational guidelines for industrial security, and follow the recommendations in the product manuals.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.cisa.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on us-cert.cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.

CISA also recommends users take the following measures to protect themselves from social engineering attacks:

No known public exploits specifically target this vulnerability. This vulnerability is not exploitable remotely.

Source:

https://us-cert.cisa.gov/ics/advisories/icsa-21-040-05