WECON LeviStudioU (Update A)

1. EXECUTIVE SUMMARY

• CVSS v3 7.8
• ATTENTION: Low skill level to exploit
• Vendor: WECON Technology Co., Ltd (WECON)
• Equipment: LeviStudioU
• Vulnerabilities: Stack-based Buffer Overflow, Heap-based Buffer Overflow, Memory Corruption

2. UPDATE INFORMATION

This updated advisory is a follow-up to the original advisory titled ICSA-19-036-03 WECON LeviStudioU that was published February 5, 2019, on the ICS webpage on us-cert.gov.

3. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow attackers to execute arbitrary code.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

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The following versions of LeviStudioU are affected:

• LeviStudioU Versions 1.8.69 and prior

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4.2 VULNERABILITY OVERVIEW

4.2.1    HEAP-BASED BUFFER OVERFLOW CWE-122

Several heap-based buffer overflow vulnerabilities have been identified, which may allow arbitrary code execution.

CVE-2019-6539 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).

4.2.2    STACK-BASED BUFFER OVERFLOW CWE-121

Multiple stack-based buffer overflow vulnerabilities may be exploited when parsing strings within project files. The process does not properly validate the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage these vulnerabilities to execute code under the context of the current process.

CVE-2019-6537 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).

4.2.3    MEMORY CORRUPTION CWE-119

A memory corruption vulnerability has been identified, which may allow arbitrary code execution.

CVE-2019-6541 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).

4.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Energy, Water and Wastewater Systems
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: China

4.4 RESEARCHER

Mat Powell, Ziad Badawi, and Natnael Samson working with Trend Micro’s Zero Day Initiative, reported these vulnerabilities to NCCIC.

5. MITIGATIONS

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WECON has produced Version 1.8.69 to fix the reported vulnerabilities in Version 1.8.56; however, exploits are still successful against this updated version. Future software updates will be made available at the following location:

http://www.we-con.com.cn/en/download_45.html

For more information contact WECON customer service:

Phone: 0086-591-87868869-894

Website: http://www.we-con.com.cn/en/message.html

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CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

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 also recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities. 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 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 these vulnerabilities. These vulnerabilities are not exploitable remotely.