CVE-2023-0811 — Omron CJ1M unit v4

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 setti

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
Omron	CJ1M SYSMAC CJ	series — All versions
Omron	CJ1M SYSMAC CJ	series — All versions
Omron	CJ1M SYSMAC CJ	series — All versions
Omron	CJ1M SYSMAC CJ	series — All versions
Omron	CJ1M SYSMAC CS	series — All versions
Omron	CJ1M SYSMAC CS	series — All versions
Omron	CJ1M SYSMAC CS	series — All versions
Omron	CJ1M SYSMAC CS	series — All versions
Omron	CJ1M SYSMAC CS	series — All versions
Omron	CJ1M SYSMAC CS	series — All versions
Omron	CJ1M SYSMAC CS	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions
Omron	CJ1M SYSMAC CP	series — All versions

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-03-16T17:41:25.525Z
• Last modified: 2025-01-16T21:42:32.824Z

09References

• www.cisa.gov — https://www.cisa.gov/news-events/ics-advisories/icsa-23-073-01
• www.ia.omron.com — https://www.ia.omron.com/product/vulnerability/OMSR-2023-001_en.pdf