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CVE-2023-0811

Omron CJ1M unit v4.0 and prior has improper access controls on the memory region where the UM password is stored. If an adversary issues a…

Critical9.1EPSS 0.62%
Published
Updated
Reserved
Assigned by
icscert

Description

Omron CJ1M unit v4.0 and prior has improper access controls on the memory region where the UM password is stored. If an adversary issues a PROGRAM AREA WRITE command to a specific memory region, they could overwrite the password. This may lead to disabling UM protections or setting a non-ASCII password (non-keyboard characters) and preventing an engineer from viewing or modifying the user program.

Timeline

  1. ID reserved

    By icscert

  2. · 31 days later

    Published

  3. · 22 months later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2023-0811, by who scored it
Scored byCVSSScoreVector
icscertCNA (assigner)3.1Critical9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
NVDNVD · Modified3.1Critical9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
EPSS (exploitation in 30 days)
0.62% · top 50% of all CVEs (7 Nov 2026)
CISA SSVC
Exploitation: none · Automatable: yes · Technical impact: partial
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.1.

Weakness

Affected products

What to do

Workaround: OMRON has released the following countermeasures for users to implement: * Enable the hardware switch to prohibit writing UM (DIP switch on front panel of the CPU Unit) * Set UM read protection password and “Prohibit from overwriting to a protected program “option. If the countermeasures cannot be applied, OMRON recommends that customers take the following mitigation measures: Security measures to prevent unauthorized access: * If the following products and versions are used, the risk of attacks by an attacker via the network can be reduced by taking the following measures. * Enable the FINS write protection function. * Select the Protect by IP Address * Minimize connection of control systems and equipment to open networks, so that untrusted devices will be unable to access them.   * Implement firewalls (by shutting down unused communications ports, limiting communications hosts, limiting access to FINS port (9600)) and isolate them from the IT network. * Use a virtual private network (VPN) for remote access to control systems and equipment. * Use strong passwords and change them frequently. * Install physical controls so that only authorized personnel can access control systems and equipment. * Scan virus to ensure safety of any USB drives or similar devices before connecting them to systems and devices. * Enforce multifactor authentication to all devices with remote access to control systems and equipment whenever possible. * Anti-virus protection * Protect any PC with access to the control system against malware and ensure installation and maintenance of up-to-date commercial grade anti-virus software protection. * Data input and output protection * Validation processing such as backup and range check to cope with unintentional modification of input/output data to control systems and devices. * Data recovery * Periodical data backup and maintenance to prepare for data loss. For more information, see Omron’s Security Advisory https://www.ia.omron.com/product/vulnerability/OMSR-2023-001_en.pdf .

References (2)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .