FATEK Automation WinProladder

1. EXECUTIVE SUMMARY

• CVSS v3 7.8
• ATTENTION: Low attack complexity
• Vendor: FATEK Automation
• Equipment: WinProladder
• Vulnerability: Integer Underflow

2. RISK EVALUATION

Successful exploitation of this vulnerability could cause execution of arbitrary code.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of FATEK Automation WinProladder, a PLC, are affected:

• WinProladder Versions 3.30 and prior

3.2 VULNERABILITY OVERVIEW

3.2.1    INTEGER UNDERFLOW (WRAP OR WRAPAROUND) CWE-191

The affected product is vulnerable to an integer underflow, which may cause an out-of-bounds write and allow an attacker to execute arbitrary code.

CVE-2021-27486 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
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Taiwan 

3.4 RESEARCHER

Francis Provencher {PRL}, working with Trend Micro’s Zero Day Initiative, reported this vulnerability to CISA.

4. MITIGATIONS

FATEK Automation is aware of the issue and is currently developing a solution. For more information, contact FATEK via email or phone: +886-2-2808-2192

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

• Only use project files from trusted sources.
• Ensure the least-privilege user principle is followed.
• 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.cisa.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.cisa.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.

• FATEK Automation