WECON PLC Editor

1. EXECUTIVE SUMMARY

• CVSS v3 7.8
• ATTENTION: Low skill level to exploit
• Vendor: WECON
• Equipment: PLC Editor
• Vulnerability: Stack-based Buffer Overflow

2. RISK EVALUATION

Successful exploitation could allow an attacker to execute code under the privileges of the application.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following version of PLC Editor, a ladder logic software, is reported to be affected:

• Version 1.3.5_20190129

Additional versions may also be vulnerable.

3.2 VULNERABILITY OVERVIEW

3.2.1    STACK-BASED BUFFER OVERFLOW CWE-121

Multiple buffer overflow vulnerabilities exist when processing project files. An attacker could use a specially crafted project file to exploit and execute code under the privileges of the application.

CVE-2019-18236 has been assigned to this vulnerability. A CVSS v3 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, Energy, Water and Wastewater Systems
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: China

3.4 RESEARCHER

Francis Provencher (PRL) and Natnael Samson (Natti) working with Trend Micro’s Zero Day Initiative reported this vulnerability to CISA.

4. MITIGATIONS

WECON has a strategy to address the issues and is currently developing a solution.

For more information contact WECON customer service on the web or phone: 0086-591-87868869-894.

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

• Only use project files from trusted sources. 
• 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 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. This vulnerability is not exploitable remotely.

• WECON