As of January 10, 2023, CISA will no longer be updating ICS security advisories for Siemens product vulnerabilities beyond the initial advisory. For the most up-to-date information on vulnerabilities in this advisory, please see Siemens’ ProductCERT Security Advisories (CERT Services | Services | Siemens Global).
1. EXECUTIVE SUMMARY
CVSS v4 7.0
ATTENTION: Low Attack Complexity
Vendor: Siemens
Equipment: TIA Portal, SIMATIC, and SIRIUS
Vulnerability: Deserialization of Untrusted Data
2. RISK EVALUATION
Successful exploitation of this vulnerability could allow an attacker to cause a type confusion and execute arbitrary code within the affected application.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following products of Siemens, are affected:
Siemens SIMATIC STEP 7 (TIA Portal) V16: All versions prior to V16 Update 7
Siemens SIMATIC STEP 7 (TIA Portal) V17: All versions prior to V17 Update 7
Siemens SIMATIC STEP 7 (TIA Portal) V18: All versions prior to V18 Update 2
Siemens SIMATIC STEP 7 Safety V16: All versions prior to V16 Update 7
Siemens SIMATIC STEP 7 Safety V17: All versions prior to V17 Update 7
Siemens SIMATIC STEP 7 Safety V18: All versions prior to V18 Update 2
Siemens SIMATIC WinCC (TIA Portal) V16: All versions prior to V16 Update 7
Siemens SIMATIC WinCC (TIA Portal) V17: All versions prior to V17 Update 7
Siemens SIMATIC WinCC (TIA Portal) V18: All versions prior to V18 Update 2
Siemens SIMATIC WinCC Unified V16: All versions prior to V16 Update 7
Siemens SIMATIC WinCC Unified V17: All versions prior to V17 Update 7
Siemens SIMATIC WinCC Unified V18: All versions prior to V18 Update 2
Siemens SIMOCODE ES V16: All versions prior to V16 Update 7
Siemens SIMOCODE ES V17: All versions prior to V17 Update 7
Siemens SIMOCODE ES V18: All versions prior to V18 Update 2
Siemens SIMOTION SCOUT TIA V5.4 SP1: All versions
Siemens SIMOTION SCOUT TIA V5.4 SP3: All versions
Siemens SIMOTION SCOUT TIA V5.5 SP1: All versions
Siemens SINAMICS Startdrive V16: All versions
Siemens SINAMICS Startdrive V17: All versions
Siemens SINAMICS Startdrive V18: All versions
Siemens SIRIUS Safety ES V17: All versions prior to V17 Update 7
Siemens SIRIUS Safety ES V18: All versions prior to V18 Update 2
Siemens SIRIUS Soft Starter ES V17: All versions prior to V17 Update 7
Siemens SIRIUS Soft Starter ES V18: All versions prior to V18 Update 2
Siemens Soft Starter ES V16: All versions prior to V16 Update 7
Siemens TIA Portal Cloud V3.0: All versions prior to V18 Update 2
3.2 Vulnerability Overview
3.2.1 DESERIALIZATION OF UNTRUSTED DATA CWE-502
Affected applications do not properly restrict the .NET BinaryFormatter when deserializing hardware configuration profiles. This could allow an attacker to cause a type confusion and execute arbitrary code within the affected application.
CVE-2023-32735 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H).
A CVSS v4 score has also been calculated for CVE-2023-32735. A base score of 7.0 has been calculated; the CVSS vector string is (CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N).
3.3 BACKGROUND
CRITICAL INFRASTRUCTURE SECTORS: Chemical, Critical Manufacturing, Energy, Transportation, and Water and Wastewater Systems.
COUNTRIES/AREAS DEPLOYED: Worldwide
COMPANY HEADQUARTERS LOCATION: Germany
3.4 RESEARCHER
Siemens reported this vulnerability to CISA.
4. MITIGATIONS
Siemens recommends updating the following products to the latest version:
SIMATIC STEP 7 (TIA Portal) V16: Update to V16 Update 7 or later
SIMATIC STEP 7 Safety V16: Update to V16 Update 7 or later
SIMATIC WinCC (TIA Portal) V16: Update to V16 Update 7 or later
SIMATIC WinCC Unified V16: Update to V16 Update 7 or later
SIMOCODE ES V16: Update to V16 Update 7 or later
Soft Starter ES V16: Update to V16 Update 7 or later
SIMATIC STEP 7 (TIA Portal) V17: Update to V17 Update 7 or later
SIMATIC STEP 7 Safety V17: Update to V17 Update 7 or later
SIMATIC WinCC (TIA Portal) V17: Update to V17 Update 7 or later
SIMATIC WinCC Unified V17: Update to V17 Update 7 or later
SIMOCODE ES V17: Update to V17 Update 7 or later
SIRIUS Safety ES V17: Update to V17 Update 7 or later
SIRIUS Soft Starter ES V17: Update to V17 Update 7 or later
SIMATIC STEP 7 (TIA Portal) V18: Update to V18 Update 2 or later
SIMATIC STEP 7 Safety V18: Update to V18 Update 2 or later
SIMATIC WinCC (TIA Portal) V18: Update to V18 Update 2 or later
SIMATIC WinCC Unified V18: Update to V18 Update 2 or later
SIMOCODE ES V18: Update to V18 Update 2 or later
SIRIUS Safety ES V18: Update to V18 Update 2 or later
SIRIUS Soft Starter ES V18: Update to V18 Update 2 or later
TIA Portal Cloud V3.0: Update to V18 Update 2 or later
Siemens has identified the following specific workarounds and mitigations users can apply to reduce risk:
All affected products: Avoid opening untrusted files from unknown sources in affected products.
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-779936 in HTML and CSAF.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as:
Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs). Recognize VPNs may have vulnerabilities, should be updated to the most recent version available, and are only as secure as the connected devices.
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 cisa.gov. 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.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov 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 exploitation specifically targeting this vulnerability has been reported to CISA at this time. This vulnerability is not exploitable remotely.
5. UPDATE HISTORY
July 11, 2024: Initial Publication