1. EXECUTIVE SUMMARY
- CVSS v3 9.8
- ATTENTION: Exploitable remotely/low attack complexity
- Vendor: FESTO
- Equipment: CODESYS
- Vulnerabilities: Partial String Comparison, Uncontrolled Resource Consumption, Memory Allocation with Excessive Size Value
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow an attacker to block legitimate user connections, crash the application, or authenticate without proper credentials.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
FESTO reports that the following products are affected:
- FESTO CODESYS Gateway Server V2: All versions
- FESTO CODESYS Gateway Server V2: prior to V2.3.9.38
3.2 VULNERABILITY OVERVIEW
3.2.1 PARTIAL STRING COMPARISON CWE-187
In CODESYS Gateway Server V2 for versions prior to V2.3.9.38 only part of the specified password is being compared to the real CODESYS Gateway password. An attacker may perform authentication by specifying a small password that matches the corresponding part of the longer real CODESYS Gateway password.
CVE-2022-31802 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).
3.2.2 UNCONTROLLED RESOURCE CONSUMPTION CWE-400
In CODESYS Gateway Server V2 an insufficient check for the activity of TCP client connections allows an unauthenticated attacker to consume all available TCP connections and prevent legitimate users or clients from establishing a new connection to the CODESYS Gateway Server V2. Existing connections are not affected and therefore remain intact.
CVE-2022-31803 has been assigned to this vulnerability. A CVSS v3.1 base score of 5.3 has been calculated; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).
3.2.3 MEMORY ALLOCATION WITH EXCESSIVE SIZE VALUE CWE-789
The CODESYS Gateway Server V2 does not verify the size of a request is within expected limits. An unauthenticated attacker may allocate an arbitrary amount of memory, which may lead to a crash of the Gateway due to an out-of-memory condition.
CVE-2022-31804 has been assigned to this vulnerability. A CVSS v3.1 base score of 7.5 has been calculated; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
3.3 BACKGROUND
- CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Germany
3.4 RESEARCHER
CERT@VDE coordinated with and supported Festo in the publication of FSA-202406.
4. MITIGATIONS
FESTO recommends users enable password protection at login in case no password is set at the controller. Please note the password configuration file is not covered by the default FFT backup and restore mechanism. The related file must be selected manually.
For more information see the associated Festo SE security advisory FSA-202406: Several Codesys Gateway v2 vulnerabilities in Codesys provided by Festo PDF or VDE-2024-059: Several Codesys Gateway v2 vulnerabilities in Codesys provided by Festo.
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). 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:
No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.
5. UPDATE HISTORY
- July 1, 2025: Initial Republication of Festo SE & Co. KG FSA-202306