CyberSecBulletin
CVE-2023-0811NVD status: Modified

CJ1M SYSMAC CJ-series: Improper Access Control

Published Updated By the CyberSecBulletin desk

CVE-2023-0811 is a critical-severity improper access control vulnerability in CJ1M SYSMAC CJ-series from Omron, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected CJ1M SYSMAC CJ-series versions: All versions. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.62% chance of exploitation within 30 days, higher than 50% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of CJ1M SYSMAC CJ-series you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on ia.omron.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
OmronCJ1M SYSMAC CJ-seriesAll versionsNot stated
OmronCJ1M SYSMAC CS-seriesAll versionsNot stated
OmronCJ1M SYSMAC CP-seriesAll versionsNot stated
OmronSysmac Cj2h-cpu64 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2h-cpu64-eip FirmwareNot specified in the recordNot stated
OmronSysmac Cj2h-cpu65 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2h-cpu65-eip FirmwareNot specified in the recordNot stated
OmronSysmac Cj2h-cpu66 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2h-cpu66-eip FirmwareNot specified in the recordNot stated
OmronSysmac Cj2h-cpu67 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2h-cpu67-eip FirmwareNot specified in the recordNot stated
OmronSysmac Cj2h-cpu68 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2h-cpu68-eip FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu11 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu12 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu13 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu14 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu15 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu31 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu32 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu33 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu34 FirmwareNot specified in the recordNot stated
OmronSysmac Cj2m-cpu35 FirmwareNot specified in the recordNot stated
OmronSysmac Cp1e-e10dr-a FirmwareNot specified in the recordNot stated
OmronSysmac Cp1e-e10dr-d FirmwareNot specified in the recordNot stated

Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.1CriticalCNA (hq.dhs.gov)
CVSS 3.19.1CriticalNVD

Official 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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

How developers prevent this class of flaw

  • Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
  • Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

More Improper Access Control vulnerabilities (CWE-284)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Improper Access Control vulnerabilities

Spotted an error? Tell us.