Mitsubishi Electric MELSEC-Q Series Ethernet Interface Module Vulnerabilities
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.
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.
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.
USE OF A BROKEN OR RISKY CRYPTOGRAPHIC ALGORITHMa
Weakly encrypted passwords are transmitted to a MELSEC-Q PLC.
CVE-2016-8370b 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
UNRESTRICTED EXTERNALLY ACCESSIBLE LOCKd
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-2016-8368e 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:N/I:N/A:H).f
Exploits that target these vulnerabilities are publicly available.
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 addressed.
Additional information about the vulnerabilities or Mitsubishi Electric's 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
Mitsubishi Electric strongly recommends that users should operate the affected device behind a firewall.
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.
Minimize network exposure to all untrusted systems and ensure that the affected products are not accessible from the Internet.
a. 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.
c. CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N, web site last accessed December 01, 2016.
d. CWE-412: Unrestricted Externally Accessible Lock, http://cwe.mitre.org/data/definitions/412.html, web site last accessed December 01, 2016.
f. CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H, web site last accessed December 01, 2016.