1. EXECUTIVE SUMMARY

CVSS v3 9.8 
ATTENTION: Exploitable remotely/low attack complexity
Vendor: Moxa
Equipment: MXsecurity Series
Vulnerabilities: Command Injection and Use of Hard-Coded Credentials

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an unauthorized user to bypass authentication or to execute arbitrary commands on the device.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Moxa reports these vulnerabilities affect the following MXsecurity Series:

MXsecurity Series: Software v1.0

3.2 VULNERABILITY OVERVIEW

3.2.1 COMMAND INJECTION CWE-77

A remote attacker, who has gained authorization privileges, could execute arbitrary commands on the device.

CVE-2023-33235 has been assigned to this vulnerability. A CVSS v3 base score of 7.2 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H).

3.2.2 USE OF HARD-CODED CREDENTIALS CWE-798

An attacker could bypass authentication for web-based application programmable interfaces (APIs).

CVE-2023-33236 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: Multiple Sectors
COUNTRIES/AREAS DEPLOYED: Worldwide
COMPANY HEADQUARTERS LOCATION: Taiwan

3.4 RESEARCHER

Simon Janz, working with Trend Micro Zero Day Initiative, reported these vulnerabilities to CISA.

4. MITIGATIONS

Moxa has developed a solution to address these vulnerabilities. Users should upgrade to software v1.0.1 or higher.

Users are encouraged to visit Moxa’s security advisory MPSA-230301 for more information.

CISA 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 they are not accessible from the Internet.
Locate control system networks and remote devices behind firewalls and isolate them from business networks.
When remote access is required, use 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 its 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 at 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.

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 exploits specifically target these vulnerabilities. These vulnerabilities are exploitable remotely. These vulnerabilities have low attack complexity.