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             AUSCERT External Security Bulletin Redistribution

          Mitsubishi Electric MELSEC-Q Series Ethernet Interface
                          Module Vulnerabilities
                              5 December 2016


        AusCERT Security Bulletin Summary

Product:           Mitsubishi Electric MELSEC-Q
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Denial of Service      -- Remote/Unauthenticated
                   Access Privileged Data -- Remote/Unauthenticated
Resolution:        Mitigation
CVE Names:         CVE-2016-8370 CVE-2016-8368 

Original Bulletin: 

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Advisory (ICSA-16-336-03)

Mitsubishi Electric MELSEC-Q Series Ethernet Interface Module Vulnerabilities

Original release date: December 01, 2016

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Security researcher Vladimir Dashchenko of Critical Infrastructure Defense 
Team, Kaspersky Lab has identified vulnerabilities in the Mitsubishi Electric
Automation, Inc. (Mitsubishi Electric) MELSEC-Q series Ethernet interface 
modules. NCCIC/ICS-CERT and JPCERT have coordinated the reported 
vulnerabilities with Mitsubishi Electric. Mitsubishi Electric has created a 
product revision for newer devices that incorporates a compensating control to
reduce the risk of exploitation for one of the identified vulnerabilities. 

These vulnerabilities could be exploited remotely. Exploits that target these
vulnerabilities are known to be publicly available.


The following MELSEC-Q series versions are affected: 

QJ71E71-100, all versions, 
QJ71E71-B5, all versions, and 
QJ71E71-B2, all versions.


Successful exploitation of these vulnerabilities may allow an attacker
to intercept weakly encrypted passwords and allow an unauthenticated remote 
attacker to cause a denial of service on the affected system. 

Impact to individual organizations depends on many factors that are unique to 
each organization. ICS-CERT recommends that organizations evaluate the impact 
of these vulnerabilities based on their operational environment, architecture, 
and product implementation.


Mitsubishi Electric is a Japan-based company that maintains offices in several
countries around the world. 

The affected products, QJ71E71-100, QJ71E71-B5, 
and QJ71E71-B2, are Ethernet interface modules that connect the MELSEC-Q 
series programmable controllers to the host network. According to Mitsubishi 
Electric, the MELSEC-Q series Ethernet interface modules are deployed across 
several sectors including Commercial Facilities, Critical Manufacturing, and 
Food and Agriculture. Mitsubishi Electric estimates that these products are 
used worldwide.



Weakly encrypted passwords are transmitted to a MELSEC-Q PLC. CVE-2016-8370[b] 
has been assigned to this vulnerability. A CVSS v3 base score of 8.6 has been 
assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N).[c]

The affected Ethernet interface module is connected to a MELSEC-Q PLC, which 
may allow a remote attacker to connect to the PLC via Port 5002/TCP and cause a 
denial of service, requiring the PLC to be reset to resume operation. 
CVE-2016-8368[e] has been assigned to this vulnerability. A CVSS v3 base score 
of 8.6 has been assigned; the CVSS vector string is 



These vulnerabilities could be exploited remotely.


Exploits that target these vulnerabilities are publicly available.


An attacker with low skill would be able to exploit these vulnerabilities.


Mitsubishi Electric has released a product revision for newer devices with 
serial numbers 18072 and later to implement IP filtering for the QJ71E71-100,
QJ71E71-B5, and QJ71E71-B2 Ethernet interface modules. Mitsubishi Electric 
reports that the IP filter function improves access prevention from external 
sources; however, the IP filter function does not completely prevent 
unauthorized access. Additional measures to encrypt communications pathway are
required, such as IPsec. The cryptographic algorithm vulnerability will not be

Additional information about the vulnerabilities or Mitsubishi 
Electrics compensating control is available by contacting a local Mitsubishi 
representative, which can be found at the following location:

https://us.mitsubishielectric.com/fa/en/about-us/distributors (link is 

Mitsubishi Electric strongly recommends that users should operate 
the affected device behind a firewall. 

ICS-CERT recommends that users take defensive measures to minimize the risk of 
exploitation of these vulnerabilities. Specifically, users should: 

Ensure that all unused ports are disabled. 

Implementing IPsec can be used to encrypt communication pathways. 

Asset owners may wish to consider implementing a Bump-in-the-Wire (BitW) 
solution to improve security. The BitW solution involves two devices inserted
in the unsecured communications pathway to provide secure communication 
between endpoints. The original devices communicate with the BitW device at 
each end. The BitW devices communicate with each other and provide encryption
services without modification of the original devices. This technology can be
applied to local area networks communications or serial communications. 

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. 

Minimize network exposure to all untrusted systems and ensure that the affected 
products are not accessible from the Internet. 

Locate control system networks and remote devices behind firewalls,
and isolate them from the business network. 

ICS-CERT reminds organizations to
perform proper impact analysis and risk assessment prior to deploying 
defensive measures. 

ICS-CERT also provides a section for control systems 
security recommended practices on the ICS-CERT web page. 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 in the ICS-CERT Technical Information Paper, 
ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation 
Strategies, that is available for download from the ICS-CERT web site. 

Organizations observing any suspected malicious activity should follow their 
established internal procedures and report their findings to ICS-CERT for 
tracking and correlation against other incidents. 

CWE-327: Use of a Broken or Risky Cryptographic Algorithm, 
http://cwe.mitre.org/data/definitions/327.html, web site last accessed 
December 01, 2016. 
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8370, NIST uses this
advisory to create the CVE web site report. This web site will be active 
sometime after publication of this advisory. 
CVSS Calculator, 
web site last accessed December 01, 2016. 
CWE-412: Unrestricted Externally
Accessible Lock, http://cwe.mitre.org/data/definitions/412.html, web site last
accessed December 01, 2016. 
e. NVD, 
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8368, NIST uses this
advisory to create the CVE web site report. This web site will be active 
sometime after publication of this advisory. 
f. CVSS Calculator, 
web site last accessed December 01, 2016.

Contact Information 
For any questions related to this report, please contact 

Email: ics-cert@hq.dhs.gov (link sends e-mail) 
Toll Free: 1-877-776-7585 
International Callers: (208) 526-0900 

For industrial control systems security
information and incident reporting: http://ics-cert.us-cert.gov 

continuously strives to improve its products and services. You can help by 
choosing one of the links below to provide feedback about this product.

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