9.1 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
7.5 High
AI Score
Confidence
High
6.4 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:L/Au:N/C:P/I:P/A:N
0.003 Low
EPSS
Percentile
70.2%
This updated advisory is a follow-up to the original advisory titled “ICSA-21-250-01 Mitsubishi Electric MELSEC iQ-R Series” that was published September 07, 2021, on the ICS webpage on cisa.gov/ICS
Successful exploitation of these vulnerabilities could allow a remote attacker unauthorized access to legitimate usernames, CPU module access, or the ability to deny access to legitimate users.
--------- Begin Update A part 1 of 2 ---------
Mitsubishi Electric reports these vulnerabilities affect the following MELSEC products:
--------- End Update A part 1 of 2 ---------
A remote attacker can leverage a brute-force attack to acquire legitimate usernames registered in the module.
CVE-2021-20594 has been assigned to this vulnerability. A CVSS v3 base score of 5.9 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N).
A remote attacker could obtain unprotected credentials by sniffing network traffic.
CVE-2021-20597 has been assigned to this vulnerability. A CVSS v3 base score of 7.4 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N).
A remote attacker could lock out a legitimate user by continually attempting to login with a known username and incorrect passwords.
CVE-2021-20598 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/C:N/I:N/A:L).
Ivan Speziale of Nozomi Networks Labs reported these vulnerabilities to CISA.
--------- Begin Update A part 2 of 2 ---------
Mitsubishi Electric has prepared the following countermeasures for CVE-2021-20594 and CVE-2021-20597 and recommends users apply updates:
Mitsubishi Electric will release patches for other products.
Users should refer to Mitsubishi Electric advisories 2021-008, 2021-009, and 2021-010 for further details.
--------- End Update A part 2 of 2 ---------
Mitsubishi Electric recommends users take the following mitigation measures to minimize the risk of exploiting these vulnerabilities:
*MELSEC iQ-R Ethernet User’s Manual (Application) 1.13 Security “IP filter”
Additional information about these vulnerabilities or Mitsubishi Electric’s compensating control is available by contacting a Mitsubishi Electric representative.
CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities. 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-12-146-01B–Targeted 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.
CISA also recommends users take the following measures to protect themselves from social engineering attacks:
No known public exploits specifically target these vulnerabilities. These vulnerabilities have a high attack complexity.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-20594
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-20597
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-20597
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-20598
cwe.mitre.org/data/definitions/200.html
cwe.mitre.org/data/definitions/522.html
cwe.mitre.org/data/definitions/645.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
twitter.com/CISAgov
twitter.com/intent/tweet?text=Mitsubishi%20Electric%20MELSEC%20iQ-R%20Series%20%28Update%20A%29+https://www.cisa.gov/news-events/ics-advisories/icsa-21-250-01
us-cert.cisa.gov/ics
us-cert.cisa.gov/ics
us-cert.cisa.gov/ics/alerts/ICS-ALERT-10-301-01
us-cert.cisa.gov/ics/recommended-practices
us-cert.cisa.gov/ics/tips/ICS-TIP-12-146-01B
us-cert.cisa.gov/ncas/tips/ST04-014
us-cert.cisa.gov/sites/default/files/publications/emailscams_0905.pdf
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:U/C:H/I:H/A:N
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www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-008_en.pdf
www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-009_en.pdf
www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-010_en.pdf
www.mitsubishielectric.com/fa/support/index.html
www.mitsubishifa.co.th/files/dl/plc/sh081257eng/sh081257engs.pdf
www.oig.dhs.gov/
www.surveymonkey.com/r/CISA-cyber-survey?product=https://www.cisa.gov/news-events/ics-advisories/icsa-21-250-01
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9.1 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
7.5 High
AI Score
Confidence
High
6.4 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:L/Au:N/C:P/I:P/A:N
0.003 Low
EPSS
Percentile
70.2%