CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:M/Au:N/C:N/I:N/A:C
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
83.0%
Successful exploitation of this vulnerability could cause a denial-of-service condition for the affected products.
Mitsubishi Electric reports the vulnerability affects the following MELSEC iQ-R series CPU module products:
A denial-of-service vulnerability due to uncontrolled resource consumption exists in MELSEC iQ-R series CPU modules. This vulnerability does not affect products when the βTo Use or Not to Use Web Serverβ parameter of CPU modules is set to βNot Use.β The default setting is βNot Use.β
CVE-2020-5666 has been assigned to this vulnerability. A CVSS v3 base score of 6.8 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H).
Xiaofei.Zhang, a researcher from China, reported this vulnerability to Mitsubishi Electric.
Mitsubishi Electric has issued the following firmware versions to address this issue:
Mitsubishi Electric also recommends the following practices:
For more information about this vulnerability and the associated mitigations, please see the vulnerability information on the Mitsubishi website.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:
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-12-146-01BβTargeted Cyber Intrusion Detection and Mitigation Strategies.
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 this vulnerability. High skill level is needed to exploit.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-5666
cisasurvey.gov1.qualtrics.com/jfe/form/SV_9n4TtB8uttUPaM6?product=https://www.cisa.gov/news-events/ics-advisories/icsa-20-317-01
cwe.mitre.org/data/definitions/400.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
twitter.com/CISAgov
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us-cert.cisa.gov/ics/alerts/ICS-ALERT-10-301-01
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us-cert.cisa.gov/ics/tips/ICS-TIP-12-146-01B
us-cert.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
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www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
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www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2020-015_en.pdf
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CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:M/Au:N/C:N/I:N/A:C
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
83.0%