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1. EXECUTIVE SUMMARY
- CVSS v3 9.8
- ATTENTION: Exploitable remotely/low attack complexity
- Vendor: FESTO, FESTO Didactic
- Equipment: CIROS Studio / Education, Automation Suite, FluidDraw, FluidSIM, MES-PC
- Vulnerability: Out-of-bounds Write
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow an attacker to gain full control of the host system, including remote code execution.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
FESTO, FESTO Didactic reports that the following products are affected:
- FESTO Didactic CIROS Studio / Education: 6.0.0 – 6.4.6
- FESTO Didactic CIROS Studio / Education: 7.0.0 – 7.1.7
- FESTO Festo Automation Suite: <= 2.6.0.481
- FESTO FluidDraw: P6 <= 6.2k
- FESTO FluidDraw: 365 <= 7.0a
- FESTO Didactic FluidSIM: 5 all versions
- FESTO Didactic FluidSIM: 6 <= 6.1c
- FESTO Didactic MES-PC: shipped before December 2023
3.2 VULNERABILITY OVERVIEW
3.2.1 OUT-OF-BOUNDS WRITE CWE-787
A heap buffer overflow vulnerability in Wibu CodeMeter Runtime network service up to version 7.60b allows an unauthenticated, remote attacker to achieve RCE and gain full access of the host system.
CVE-2023-3935 has been assigned to this vulnerability. A CVSS v3.1 base score of 9.8 has been calculated; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
3.3 PRODUCT IMPACT
Product-specific impact for an affected product vulnerable to the CVE:
- CVE-2023-3935
- (FESTO FluidDraw; FESTO FluidDraw; FESTO Festo Automation Suite): A CVSS v3.1 base score of 9.8 has been calculated; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
3.4 BACKGROUND
- CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Germany
3.5 RESEARCHER
CERT@VDE coordinated with and supported Festo in the publication of FSA-202305.
4. MITIGATIONS
FESTO, FESTO Didactic have identified the following specific workarounds and mitigations users can apply to reduce risk:
- FESTO Didactic CIROS Studio / Education 6.0.0 – 6.4.6, FESTO Didactic FluidSIM 5 all versions, FESTO Didactic FluidSIM 6 <= 6.1c, FESTO Didactic CIROS Studio / Education 7.0.0 – 7.1.7, FESTO Didactic MES-PC shipped before December 2023: Update CodeMeter Runtime to version >= 7.60c The latest version of CodeMeter Runtime can be downloaded from WIBU System’s web site.
- FESTO Festo Automation Suite <= 2.6.0.481: Planned Fix in Summer Release 2024
- FESTO FluidDraw P6 <= 6.2k, FESTO FluidDraw 365 <= 7.0a: Update to the latest version.
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.
5. UPDATE HISTORY
- July 1, 2025: Initial Republication of Festo SE & Co. KG FSA-202305
