Yokogawa WideField3

1. EXECUTIVE SUMMARY

• CVSS v3 2.8
• ATTENTION: Exploitable remotely/low skill level to exploit
• Vendor: Yokogawa
• Equipment: Main equipment
• Vulnerability: Buffer Copy Without Checking Size of Input

2. RISK EVALUATION

Successful exploitation of this vulnerability could terminate the program abnormally.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Yokogawa reports that the vulnerability affects the tool for programming FA-M3 PLCs:

• WideField3 R1.01 - R4.03

3.2 VULNERABILITY OVERVIEW

3.2.1     BUFFER COPY WITHOUT CHECKING SIZE OF INPUT CWE-120

A buffer overflow could be caused when a user loads a maliciously crafted project file. 

CVE-2020-16232 has been assigned to this vulnerability. A CVSS v3 base score of 2.8 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Energy, Food and Agriculture
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Japan

3.4 RESEARCHER

Parity Dynamics reported this vulnerability to CISA.

4. MITIGATIONS

Yokogawa has prepared revision R4.04 to address this vulnerability and recommends that users switch to this revision.

For more information about this vulnerability and the associated mitigations, please see Yokogawa’s security advisory report YSAR-20-0002

CISA recommends users take the following measures to protect themselves from social engineering attacks: 

• Do not click web links or open unsolicited attachments in 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.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
• When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that 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 us-cert.gov. Several recommended 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 on us-cert.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.



Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.

No known public exploits specifically target this vulnerability. 

• Yokogawa