11 May 2021
KLCERT-20-020: Moxa NPort IA5000A Series. Using the Telnet service
Vendor
Moxa
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CVE-IDS
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KLCERT
KLCERT-20-020
Timeline
Timeline
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Kaspersky ICS CERT advisory published
11 May 2021
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Moxa published the advisory
28 April 2021
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Moxa confirmed the vulnerability
24 August 2020
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Vulnerability reported
14 August 2020
Description
CVSS v3
Exploitability
Remotely exploitable: network access to port 23/TCP is required
Attack complexity
Privilege required
User interaction
Impact
Existence of exploit
Unknown
Affected products
NPort IA5150A-IEX
NPort IA5150A-T-IEX
NPort IA5150A-T
NPort IA5150A
NPort IA5150AI-IEX
NPort IA5150AI-T-IE
NPort IA5150AI-T
NPort IA5150AI
NPort IA5250A-IEX
NPort IA5250A-T-IEX
NPort IA5250A-T
NPort IA5250A
NPort IA5250AI-IEX
NPort IA5250AI-T-IE
NPort IA5250AI-T
NPort IA5250AI
NPort IA5450A-T
NPort IA5450A
NPort IA5450AI-T
NPort IA5450AI
Mitigation
Vendor mitigation
Moxa products can disable the Telnet service to mitigate this risk. Please refer to the Console Settings section in the user manual for more details. Firmware version 1.5 or higher will disable Telnet by default on the NPort IA5150A/IA5250A Series. Firmware version 2.0 or higher will disable Telnet by default on the NPort IA5450A Series.
Link to Moxa’s advisory: https://www.moxa.com/en/support/product-support/security-advisory/nport-ia5000a-serial-device-servers-vulnerabilities
KL mitigation
Set up a border firewall (or a similar network traffic control solution) passing traffic into the device’s network segment to allow traffic to port 23/TCP from authorized parties only.
Disable Telnet service on NPort device if it is possible in your environments
Firewall. Configure the firewall to restrict access to the industrial network in such a way that only essential communications from authorized sources are allowed. This will help reduce the attack surface. Make sure that the firewall restrictions do not affect core business workflows.
VPN. Use virtual private networks (VPN) to secure remote access to the industrial network. A VPN encrypts network traffic between VPN clients and the VPN server, as well as providing secure authorized access to local resources on the company’s internal network. Traffic encryption protects against traffic eavesdropping attacks, including man-in-the-middle (MitM) and other types of traffic analysis attacks.
Network monitoring. Implement a network intrusion detection solution (NIDS). A comprehensive IDS solution is capable of detecting unusual network connections and abnormal traffic sent to the device, providing timely information about various suspicious activities and sufficiently reducing the attacker’s chances of successful exploitation.
Network segmentation. Compartmentalize your network: implement network segmentation and strict access control for each segment to provide more comprehensive and effective protection against a wide range of threats. Proper network segmentation prevents attackers from reaching critical assets in the event of a network breach
Kaspersky publishes information on newly identified vulnerabilities in order to raise user awareness of the IT security threats detected. Kaspersky does not make any guarantees in respect of information received from vendors of products in which vulnerabilities have been identified, which is included in the following sections of the advisory: Affected Products, Vendor Mitigation.
