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). 

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1. EXECUTIVE SUMMARY

CVSS v3 7.8
ATTENTION: Low attack complexity
Vendor: Siemens
Equipment: COMOS
Vulnerabilities: Out-of-bounds Write, Use After Free

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to execute arbitrary code.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Siemens COMOS, a unified data platform, are affected:

COMOS: All versions prior to V10.5

3.2 Vulnerability Overview

3.2.1 OUT-OF-BOUNDS WRITE CWE-787

An issue was discovered in Open Design Alliance Drawings SDK before 2024.12. A corrupted value of number of sectors used by the Fat structure in a crafted DGN file leads to an out-of-bounds write. An attacker can leverage this vulnerability to execute code in the context of the current process.

CVE-2023-5180 has been assigned to this vulnerability. A CVSS v3.1 base score of 7.8 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.2 USE AFTER FREE CWE-416

Open Design Alliance Drawings SDK (versions before 2024.1) contains a use-after-free vulnerability that could be triggered while parsing specially crafted DWG file. An attacker could leverage this in conjunction with other vulnerabilities to execute arbitrary code.

CVE-2023-26495 has been assigned to this vulnerability. A CVSS v3.1 base score of 7.8 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:N/UI:R/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

Siemens reported these vulnerabilities to CISA.

4. MITIGATIONS

Siemens recommends users update to the latest version:

Update to V10.5 or later version

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

CVE-2023-5180, CVE-2023-26495: Ensure all files imported into the affected product originate from a trusted source and are transmitted over secure channels

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-659443 in HTML and CSAF.

CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities, 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), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is 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/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.

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/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 exploitation specifically targeting these vulnerabilities has been reported to CISA at this time. These vulnerabilities are not exploitable remotely.

5. UPDATE HISTORY

August 15, 2024: Initial Publication