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AUSCERT External Security Bulletin Redistribution
Multiple vulnerabilities have been identified in Kunbus
PR100088 Modbus Gateway
6 February 2019
AusCERT Security Bulletin Summary
Product: Kunbus PR100088 Modbus Gateway
Operating System: Network Appliance
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Denial of Service -- Existing Account
CVE Names: CVE-2019-6533 CVE-2019-6529 CVE-2019-6527
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Kunbus PR100088 Modbus Gateway
Original release date: February 05, 2019
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1. EXECUTIVE SUMMARY
CVSS v3 10.0
ATTENTION: Exploitable remotely/low skill level to exploit
Equipment: PR100088 Modbus gateway
Vulnerabilities: Improper Authentication, Missing Authentication for Critical
Function, Improper Input Validation
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow an attacker to
achieve remote code execution and/or cause a denial-of-service condition.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of PR100088 Modbus gateway are affected:
PR100088 Modbus gateway: All versions prior to Release R02 (or Software
3.2 VULNERABILITY OVERVIEW
3.2.1 IMPROPER AUTHENTICATION CWE-287
An attacker may be able change the password for an admin user who is currently
or previously logged in, provided the device has not been restarted.
CVE-2019-6527 has been assigned to this vulnerability. A CVSS v3 base score of
9.6 has been calculated; the CVSS vector string is
3.2.2 MISSING AUTHENTICATION FOR CRITICAL FUNCTION CWE-306
Registers used to store Modbus values can be read and written from the web
interface without authentication.
CVE-2019-6533 has been assigned to this vulnerability. A CVSS v3 base score of
10.0 has been calculated; the CVSS vector string is
3.2.3 IMPROPER INPUT VALIDATION CWE-20
An attacker could specially craft an FTP request that could crash the device.
CVE-2019-6529 has been assigned to this vulnerability. A CVSS v3 base score of
4.9 has been calculated; the CVSS vector string is
CRITICAL INFRASTRUCTURE SECTORS: Communication
COUNTRIES/AREAS DEPLOYED: Worldwide
COMPANY HEADQUARTERS LOCATION: Germany
Nicolas Merle of Applied Risk reported these vulnerabilities to NCCIC. NCCIC
coordinated these vulnerabilities with BSI Germany.
Kunbus recommends the following:
Update to Version R02; the updated file can be downloaded from the link below
(installation instructions can be found in the readme file included in the
These devices are not intended to be used in a public network. Rather, these
devices are intended for use in an industrial environment with a protected
NCCIC recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:
Minimize network exposure for all control system devices and/or systems, and
ensure that they are not accessible from the Internet.
Locate control system networks and remote devices behind firewalls, and
isolate them from the business network.
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.
NCCIC reminds organizations to perform proper impact analysis and risk
assessment prior to deploying defensive measures.
NCCIC 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 on the ICS-CERT website 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 NCCIC 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 NCCIC at:
Toll Free: 1-888-282-0870
For industrial control systems cybersecurity information:
or incident reporting: https://ics-cert.us-cert.gov/Report-Incident?
The NCCIC continuously strives to improve its products and services. You can
help by choosing one of the links below to provide feedback about this
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