FATEK Automation WinProladder

1. EXECUTIVE SUMMARY

• CVSS v3 7.8
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: FATEK Automation
• Equipment: WinProladder
• Vulnerabilities: Out-of-bounds Write, Out-of-bounds Read, Unexpected Sign Extension, Stack-based Buffer Overflow, Improper Restriction of Operations within the Bounds of a Memory Buffer, Use After Free

2. RISK EVALUATION

Successful exploitation of these vulnerabilities may allow arbitrary code execution, remote code execution, heap corruption, and unauthorized information disclosure.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

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

• WinProladder: Versions 3.30 and prior

3.2 VULNERABILITY OVERVIEW

3.2.1    USE AFTER FREE CWE-416

A use after free vulnerability may be exploited when a valid user opens a malformed project file, which may allow arbitrary code execution.

CVE-2021-38438 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).

3.2.2    OUT-OF-BOUNDS WRITE CWE-787

The affected product lacks proper validation of user-supplied data when parsing project files, which could result in an out-of-bounds write. An attacker could leverage this vulnerability to execute arbitrary code.

CVE-2021-38426 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).

3.2.3    UNEXPECTED SIGN EXTENSION CWE-194

The affected product lacks proper validation of user-supplied data when parsing project files, which could result in an unexpected sign extension. An attacker could leverage this vulnerability to execute arbitrary code.

CVE-2021-38434 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).

3.2.4    STACK-BASED BUFFER OVERFLOW CWE-121

The affected product lacks proper validation of user-supplied data when parsing project files, which could result in a stack-based buffer overflow. An attacker could leverage this vulnerability to execute arbitrary code.

CVE-2021-38430 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).

3.2.5    IMPROPER RESTRICTION OF OPERATIONS WITHIN THE BOUNDS OF A MEMORY BUFFER CWE-119

The affected product lacks proper validation of user-supplied data when parsing project files, which could result in a memory-corruption condition. An attacker could leverage this vulnerability to execute arbitrary code in the context of the current process.

CVE-2021-38436 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).

3.2.6    IMPROPER RESTRICTION OF OPERATIONS WITHIN THE BOUNDS OF A MEMORY BUFFER CWE-119

The affected product lacks proper validation of user-supplied data when parsing project files, which could result in a heap-corruption condition. An attacker could leverage this vulnerability to execute code in the context of the current process.

CVE-2021-38442 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).

3.2.7    OUT-OF-BOUNDS READ CWE-125

The affected product is vulnerable to an out-of-bounds read, which may allow an attacker to read unauthorized information.

CVE-2021-38440 has been assigned to this vulnerability. A CVSS v3 base score of 3.3 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Taiwan

3.4 RESEARCHER

xina1i and Natnael Samson (@NattiSamson), working with Trend Micro’s Zero Day Initiative, reported these vulnerabilities to CISA.

4. MITIGATIONS

FATEK Automation has not responded to requests to work with CISA to mitigate these vulnerabilities. Users of these affected products are invited to contact FATEK customer support for additional information.

CISA also 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 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 these vulnerabilities.

• FATEK Automation