1. EXECUTIVE SUMMARY

CVSS v3 7.3
ATTENTION: Low attack complexity 
Vendor: Siemens 
Equipment: TIA Portal 
Vulnerability: Improper Input Validation 

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to achieve arbitrary code execution. 

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following software from Siemens is affected: 

TIA Portal V15: All versions 
TIA Portal V16: All versions 
TIA Portal V17: All versions 
TIA Portal V18: All versions prior to v18 Update 1 

3.2 VULNERABILITY OVERVIEW

3.2.1 IMPROPER INPUT VALIDATION CWE-20 

Affected products contain a path traversal vulnerability that could allow the creation or overwriting of arbitrary files in the engineering system. If the user is tricked into opening a malicious PC system configuration file, an attacker could exploit this vulnerability to achieve arbitrary code execution. 

CVE-2023-26293 has been assigned to this vulnerability. A CVSS v3 base score of 7.3 has been calculated; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L). 

3.3 BACKGROUND

CRITICAL INFRASTRUCTURE SECTORS: Multiple 
COUNTRIES/AREAS DEPLOYED: Worldwide 
COMPANY HEADQUARTERS LOCATION: Germany 

3.4 RESEARCHER

Siemens reported this vulnerability to CISA. 

4. MITIGATIONS

Siemens has released an update for TIA Portal V18 and recommends updating to the latest version. Siemens is preparing further updates and recommends specific countermeasures for products where updates are not, or not yet, available: 

TIA Portal V18: Update to V18 Update 1 or later version. 

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

Avoid opening untrusted project files or PC system configuration files. 

As a general security measure, Siemens strongly 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 the recommendations in the product manuals. Additional information on industrial security by Siemens can be found at the Siemens Industrial Security web page. 

For further inquiries on security vulnerabilities in Siemens’ products and solutions, users should contact the Siemens ProductCERT. 

For more information, see the associated Siemens security advisory SSA-116924 in HTML and CSAF.  

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability.

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 at cisa.gov/ics. Several CISA products detailing cyber defense best 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 at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report 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: 

Do not click web links or open attachments in unsolicited email messages. 
Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams. 
Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks. 

No known public exploits specifically target this vulnerability.