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1. EXECUTIVE SUMMARY

CVSS v3 9.8
ATTENTION: Exploitable remotely/low attack complexity
Vendor: Weintek
Equipment: cMT3000 CMI Web CGI
Vulnerabilities: Stack-based Buffer Overflow, OS Command Injection

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to hijack control flow and bypass login authentication or execute arbitrary commands.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following Weintek products are affected:

cMT-FHD: OS version 20210210 or prior.
cMT-HDM: OS version 20210204 or prior.
cMT3071: OS version 20210218 or prior.
cMT3072: OS version 20210218 or prior.
cMT3103: OS version 20210218 or prior.
cMT3090: OS version 20210218 or prior.
cMT3151: OS version 20210218 or prior.

3.2 Vulnerability Overview

3.2.1 STACK-BASED BUFFER OVERFLOW CWE-121

In Weintek’s cMT3000 HMI Web CGI device, the cgi-bin command_wb.cgi contains a stack-based buffer overflow, which could allow an anonymous attacker to hijack control flow and bypass login authentication.

CVE-2023-38584 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.2 IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS USED IN AN OS COMMAND (‘OS COMMAND INJECTION’) CWE-78

In Weintek’s cMT3000 HMI Web CGI device, an anonymous attacker can execute arbitrary commands after login to the device.

CVE-2023-40145 has been assigned to this vulnerability. A CVSS v3 base score of 8.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

3.2.3 STACK-BASED BUFFER OVERFLOW CWE-121

In Weintek’s cMT3000 HMI Web CGI device, the cgi-bin codesys.cgi contains a stack-based buffer overflow, which could allow an anonymous attacker to hijack control flow and bypass login authentication.

CVE-2023-43492 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/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

Hank Chen (PSIRT and Threat Research of TXOne Networks) reported these vulnerabilities to CISA.

4. MITIGATIONS

Weintek recommends users follow their Upgrade Instructions to update the following products to the latest versions:

cMT-FHD: OS version 20210211
cMT-HDM: OS version 20210205
cMT3071: OS version 20210219
cMT3072: OS version 20210219
cMT3103: OS version 20210219
cMT3090: OS version 20210219
cMT3151: OS version 20210219

For additional information, refer to Weintek’s security bulletin.

CISA recommends users take defensive measures to minimize the risk of exploitation of this these vulnerabilities, such as:

Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize 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 cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

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

No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.

5. UPDATE HISTORY

October 12, 2023: Initial Publication