1. EXECUTIVE SUMMARY
- CVSS v3 8.6
- ATTENTION: Exploitable remotely/low attack complexity
- Vendor: Mitsubishi Electric
- Equipment: MELSEC iQ-R Series
- Vulnerability: Improper Input Validation
2. RISK EVALUATION
Successful exploitation of this vulnerability could allow a remote unauthenticated attacker to cause a denial-of-service condition on a target product by sending specially crafted packets.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following Mitsubishi Electric MELSEC iQ-R Series products are affected:
- RJ71EN71: Firmware version “65” and prior
- R04/08/16/32/120ENCPU: Network part firmware version “65” and prior
3.2 VULNERABILITY OVERVIEW
3.2.1 IMPROPER INPUT VALIDATION CWE-20
MELSEC iQ-R Series RJ71EN71 products with firmware versions prior to “65” and R04/08/16/32/120ENCPU products with Network firmware versions prior to “65” are vulnerable to improper input validation. A remote unauthenticated user could cause a denial-of-service condition on a target product by sending specially crafted packets. A system reset is required to recover from a denial-of-service condition.
CVE-2022-40265 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:C/C:N/I:N/A:H).
3.3 BACKGROUND
- CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Japan
3.4 RESEARCHER
Mitsubishi Electric reported this vulnerability to CISA.
4. MITIGATIONS
Mitsubishi Electric has fixed the vulnerability in the following MELSEC iQ-R Series products:
- RJ71EN71: Update firmware version to “66” or later.
- R04/08/16/32/120ENCPU: Update network part firmware version to “66” or later.
Users should refer to the following product manual for instructions to update firmware:
- MELSEC iQ-R Module Configuration Manual “Firmware Update Function.”
Mitsubishi Electric recommends users take the following mitigation measures to minimize the risk of an unauthenticated user exploiting this vulnerability:
- Use a firewall, virtual private network (VPN), etc. to prevent unauthorized access when internet access is required.
- Use the product within a local area network (LAN)
- Block access from untrusted networks and hosts through firewalls.
- Use the IP filter function to restrict the accessible IP addresses.
Note: For using the IP filter function, users should see MELSEC iQ-R Ethernet User’s Manual (Application) Security “IP filter”
Users can refer to the Mitsubishi Electric advisory for further details.
CISA 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 they are not accessible from the Internet.
- Locate control system networks and remote devices behind firewalls and isolate them from business networks.
- 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.
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