As of June 15, 2022, this site no longer supports Internet Explorer. Please use another browser for the best experience on our site.

Product support

Security Advisories

SUMMARY

Security Enhancement: Modbus/TCP Discrete Input Access

Using function code 2, Modbus can read the discrete inputs from a Modbus slave, which is commonly used by SCADA and DCS field devices. Discrete inputs represent binary (i.e boolean) values that often map to switches, relays, or other sensors. A sample of discrete inputs read from the device are provided by the plugin output. The ability to read discrete inputs may help an attacker profile a system. (Source: Tenable Nessus)

As this issue is assessed as medium severity, users may evaluate their environment and schedule the update in the next maintenance or update cycle.

AFFECTED PRODUCTS AND SOLUTIONS

Solutions

Moxa has developed appropriate solutions to enhance the security. The solutions for the affected products are listed in the following table: 

Product Series Affected Versions Solutions

ioLogik E2200 Series

  • (E2210)
  • (E2212)
  • (E2214)
  • (E2240)
  • (E2242)
  • (E2260)
  • (E2262)

Firmware

  • v3.13 and earlier 
  • v3.14 and earlier 
  • v3.12 and earlier 
  • v3.12 and earlier 
  • v3.12 and earlier 
  • v3.13 and earlier 
  • v3.12 and earlier 
Please refer to Mitigations

 

Mitigations

To mitigate the risk, we recommend the following actions:

  • Users are advised to use the “Accessible IP Settings” feature to restrict the host IP addresses that are allowed to access Modbus/TCP communication, preventing unauthorized remote access and reduces the risk of device identification information disclosure.
  • Refer to the General Security Recommendations section to further strengthen your security context.

 

General Security Recommendations

To safeguard devices and networks, we recommend implementing the following recommendations to mitigate potential risks:

  1. Restrict Network Access
    • Use firewalls or access control lists (ACLs) to limit communication to trusted IP addresses and networks.
    • Segregate operational networks from other networks (e.g., enterprise networks) using VLANs or physical separation.
  2. Minimize Exposure
    • Avoid exposing devices directly to the Internet.
    • Disable unused network services and ports to reduce the attack surface.
  3. Enhance Device Authentication and Access Control
    • Implement multi-factor authentication (MFA) for accessing critical systems.
    • Use role-based access control (RBAC) to enforce the principle of least privilege.
  4. Regularly Update Firmware and Software
    • Keep devices updated with the latest firmware versions and security patches.
    • Establish a regular patch management schedule to address newly identified vulnerabilities.
  5. Secure Remote Access
    • Use encrypted communication protocols (e.g., VPN, SSH) for remote access.
    • Restrict remote access to authorized personnel only and enforce strong authentication mechanisms.
  6. Implement Anomaly Detection Techniques
    • Monitor network traffic and device behavior for unusual or unauthorized activities.
    • Use tools or techniques that can identify anomalies and provide alerts for potential threats.
  7. Implement Logging and Monitoring
    • Enable event logging and maintain audit trails on devices.
    • Regularly review logs for anomalies and unauthorized access attempts.
  8. Conduct Regular Security Assessments
    • Perform vulnerability assessments to identify potential risks.
    • Regularly review device configurations to ensure compliance with security policies.

 

Revision History:

VERSION DESCRIPTION RELEASE DATE
1.0 First release October 21, 2025

Relevant Products

ioLogik E2200 Series ·

  •   Print this page
  • You can manage and share your saved list in My Moxa
Let’s get that fixed

If you are concerned about a potential cybersecurity vulnerability, please contact us and one of technical support staff will get in touch with you.

Report a Vulnerability
Added To Bag
You have some items waiting in your bag; click here to finish your quote!
Feedback