Operating System:

[Appliance]

Published:

20 December 2019

Protect yourself against future threats.

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2019.4728
           Advisory (icsa-19-353-01) Moxa EDS Ethernet Switches
                             20 December 2019

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Moxa EDS Ethernet Switches
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-19707  

Original Bulletin: 
   https://www.us-cert.gov/ics/advisories/icsa-19-353-01

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ICS Advisory (ICSA-19-353-01)

Moxa EDS Ethernet Switches

Original release date: December 19, 2019

Legal Notice

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provided"as is" for informational purposes only. The Department of Homeland
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For more information about TLP, see http://www.us-cert.gov/tlp/ .



1. EXECUTIVE SUMMARY

  o CVSS v3 7.5
  o ATTENTION: Exploitable remotely/low skill level to exploit
  o Vendor: Moxa
  o Equipment: EDS-G508E, EDS-G512E, and EDS-G516E Series Ethernet Switches
  o Vulnerability: Uncontrolled Resource Consumption

2. RISK EVALUATION

Successful exploitation of this vulnerability could cause the target device to
go out of service.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Moxa reports that the vulnerability affects the following products:

  o EDS-G508E Series: Firmware Version 6.0 and prior
  o EDS-G512E Series: Firmware Version 6.0 and prior
  o EDS-G516E Series: Firmware Version 6.0 and prior

3.2 VULNERABILITY OVERVIEW

3.2.1 UNCONTROLLED RESOURCE CONSUMPTION CWE-400

PROFINET DCE-RPC diagnostic packets can cause the device to enter a
denial-of-service condition.

CVE-2019-19707 has been assigned to this vulnerability. A CVSS v3 base score of
7.5 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:N/I:N/A:H ).

3.3 BACKGROUND

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

3.4 RESEARCHER

Yuval Ardon and Matan Dobrushin of Otorio reported this vulnerability to CISA.

4. MITIGATIONS

Moxa has developed a patch to address the vulnerability. Users can contact Moxa
Technical Support (logon required) for the security patch. Users can also view
Moxa's security advisory published on this vulnerability.

CISA recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:

  o Minimize network exposure for all control system devices and/or systems,
    and ensure that they are not accessible from the Internet .
  o Locate control system networks and remote devices behind firewalls, and
    isolate them from the business network.
  o 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 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.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 this vulnerability.

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