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AUSCERT External Security Bulletin Redistribution
Advisory (icsa-21-336-08) Hitachi Energy RTU500 series
3 December 2021
AusCERT Security Bulletin Summary
Product: Hitachi Energy RTU500 series
Operating System: Network Appliance
Impact/Access: Denial of Service -- Remote/Unauthenticated
Access Confidential Data -- Remote/Unauthenticated
CVE Names: CVE-2021-3517 CVE-2020-24977 CVE-2020-1968
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ICS Advisory (ICSA-21-336-08)
Hitachi Energy RTU500 series
Original release date: December 02, 2021
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1. EXECUTIVE SUMMARY
o CVSS v3 8.6
o ATTENTION: Exploitable remotely/low attack complexity
o Vendor: Hitachi Energy
o Equipment: RTU500 series
o Vulnerabilities: Observable Discrepancy, Buffer Over-read, Out-of-bounds
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow an attacker to
eavesdrop on traffic, retrieve information from memory, or cause a
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of the RTU500 series, a remote terminal unit, are
o RTU500 series CMU Firmware: Version 11.*
o RTU500 series CMU Firmware: Version 12.0.*
o RTU500 series CMU Firmware: Version 12.2.*
o RTU500 series CMU Firmware: Version 12.4.*
o RTU500 series CMU Firmware: Version 12.6.*
o RTU500 series CMU Firmware: Version 12.7.*
o RTU500 series CMU Firmware: Version 13.0.*
o RTU500 series CMU Firmware: Version 13.1.*
o RTU500 series CMU Firmware: Version 13.2.1
3.2 VULNERABILITY OVERVIEW
3.2.1 OBSERVABLE DISCREPANCY CWE-203
The Raccoon attack exploits a flaw in the TLS specification, which can lead to
an attacker computing pre-master secret in connections that have used a
Diffie-Hellman- based cipher suite. An attacker can then eavesdrop on all
encrypted communications sent over the exploited TLS connection.
CVE-2020-1968 has been assigned to this vulnerability. A CVSS v3 base score of
3.7 has been calculated; the CVSS vector string is ( AV:N/AC:H/PR:N/UI:N/S:U/
3.2.2 BUFFER OVER-READ CWE-126
There is a global buffer over-read vulnerability in xmlEncodeEntitiesInternal
in the affected libxml2/entities.c.
CVE-2020-24977 has been assigned to this vulnerability. A CVSS v3 base score of
6.5 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
3.2.3 OUT-OF-BOUNDS READ CWE-125
A vulnerability exists in the xml entity encoding functionality of the affected
libxml2. An attacker can use a specially crafted file to trigger an
CVE-2021-3517 has been assigned to this vulnerability. A CVSS v3 base score of
8.6 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
o CRITICAL INFRASTRUCTURE SECTORS: Energy
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Switzerland
Hitachi Energy reported these vulnerabilities to CISA.
Hitachi Energy recommends users take the following actions at the earliest
o RTU500 series CMU Firmware Version 11.*: This product version is
end-of-life (EOL). Upgrade to a non-affected support version. See below for
the current mitigation strategy.
o RTU500 series CMU Firmware Version 12.0.1 - 12.0.13: Update to RTU500
series CMU Firmware Version 12.0.14 (to be released by end-of-February
2022). See below for the current mitigation strategy.
o RTU500 series CMU Firmware Version 12.2.1 - 12.2.10: Update to RTU500
series CMU Firmware as of Version 12.2.11
o RTU500 series CMU Firmware Version 12.4.1 - 12.4.10: Update to RTU500 CMU
Firmware as of Version 12.4.11 (to be released by end-of-January 2022). See
below for the current mitigation strategy.
o RTU500 series CMU Firmware Version 12.6.1 - 12.6.6: Update to RTU500 series
CMU firmware as of Version 12.6.7 (to be released by end-of-December 2021).
See below for the current mitigation strategy.
o RTU500 series CMU Firmware Version 12.7.1: Update to RTU500 series CMU
Firmware as of Version 12.7.2
o RTU500 series CMU Firmware Version 13.0.1 - 13.0.2: Upgrade to the latest
RTU500 series CMU Firmware as of Version 13.2.3. See below for the current
o RTU500 series CMU Firmware Version 13.1.1 - 13.1.2: Upgrade to the latest
RTU500 series CMU Firmware as of Version 13.2.3. See below for the current
o RTU500 series CMU Firmware Version 13.2.1: Upgrade to the latest RTU500
series CMU Firmware as of Version 13.2.3. See below for the current
Hitachi Energy recommends the following security practices and firewall
configurations to help protect process control networks from attacks that
originate from outside the network:
o Physically protect process control systems from direct access by
o Do not directly connect to the Internet.
o Separate from other networks by means of a firewall system that has a
minimal number of ports exposed.
o Process control systems should not be used for Internet surfing, instant
messaging, or receiving e-mails.
o Portable computers and removable storage media should be carefully scanned
for viruses before they are connected to a control system.
Please see Hitachi Energy advisory 8DBD000064 for additional mitigation and
CISA recommends users take defensive measures to minimize the risk of
exploitation of these vulnerabilities. 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 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 on us-cert.cisa.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.cisa.gov in the Technical Information Paper,
ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation
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 these vulnerabilities.
For any questions related to this report, please contact the CISA at:
Toll Free: 1-888-282-0870
CISA 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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