CyberSecBulletin
CVE-2023-27396NVD status: Modified

Multiple OMRON products which implement FINS…: Missing Authentication for Critical Functionality

Published Updated By the CyberSecBulletin desk

CVE-2023-27396 is a critical-severity missing authentication for critical functionality vulnerability in Multiple OMRON products which implement FINS protocol from Omron, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 1.37% chance of exploitation within 30 days, higher than 72% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of Multiple OMRON products which implement FINS protocol you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on fa.omron.co.jp 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
OMRONMultiple OMRON products which implement FINS protocolNot specified in the recordNot stated
OmronCs1w-eip21 FirmwareNot specified in the recordNot stated
OmronCs1w-spu01-v2 FirmwareNot specified in the recordNot stated
OmronCs1w-spu02-v2 FirmwareNot specified in the recordNot stated
OmronCs1w-etn21 FirmwareNot specified in the recordNot stated
OmronCs1w-clk FirmwareNot specified in the recordNot stated
OmronCs1w-fln22 FirmwareNot specified in the recordNot stated
OmronCs1w-drm21-v1 FirmwareNot specified in the recordNot stated
OmronCs1w-nc271 FirmwareNot specified in the recordNot stated
OmronCs1w-nc471 FirmwareNot specified in the recordNot stated
OmronCs1w-ncf71 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu35 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu34 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu33 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu32 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu31 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu15 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu14 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu13 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu12 FirmwareNot specified in the recordNot stated
OmronCj2m-cpu11 FirmwareNot specified in the recordNot stated
OmronCp1w-cif01 FirmwareNot specified in the recordNot stated
OmronCp1w-cif11 FirmwareNot specified in the recordNot stated
OmronCp1w-cif12-v1 FirmwareNot specified in the recordNot stated
OmronCj2m-md211 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
HighAll data handled by the component can be read.
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:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 3.19.8CriticalCISA (ADP)

Official description

FINS (Factory Interface Network Service) is a message communication protocol, which is designed to be used in closed FA (Factory Automation) networks, and is used in FA networks composed of OMRON products. Multiple OMRON products that implement FINS protocol contain following security issues -- (1)Plaintext communication, and (2)No authentication required. When FINS messages are intercepted, the contents may be retrieved. When arbitrary FINS messages are injected, any commands may be executed on, or the system information may be retrieved from, the affected device. Affected products and versions are as follows: SYSMAC CS-series CPU Units, all versions, SYSMAC CJ-series CPU Units, all versions, SYSMAC CP-series CPU Units, all versions, SYSMAC NJ-series CPU Units, all versions, SYSMAC NX1P-series CPU Units, all versions, SYSMAC NX102-series CPU Units, all versions, and SYSMAC NX7 Database Connection CPU Units (Ver.1.16 or later)

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

The underlying weakness: Missing Authentication for Critical Functionality

The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

How developers prevent this class of flaw

  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
  • When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to require strong authentication for users who should be allowed to access the data.

More Missing Authentication for Critical Functionality vulnerabilities (CWE-306)

Timeline

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

References

Third-party and government advisories

Recent Missing Authentication for Critical Functionality vulnerabilities

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