PatchSiren cyber security CVE debrief

CVE-2024-1480 Unitronics CVE debrief

A critical vulnerability in Unitronics Vision Legacy series PLCs allows remote, unauthenticated attackers to retrieve the 'Information Mode' password in plaintext. This exposes affected industrial control systems to unauthorized access and potential operational disruption. The vulnerability carries a HIGH severity CVSS 3.1 score of 7.5, reflecting its network attack vector, low complexity, and high confidentiality impact. CISA published this advisory on April 18, 2024, with an update on April 30, 2024 adding vendor mitigations. The affected products span five Vision Legacy PLC models: Vision 120, 230, 280, 290, and 530, all versions. No known exploitation in ransomware campaigns has been reported.

Vendor: Unitronics
Product: Vision 230
CVSS: HIGH 7.5
CISA KEV: Not listed in stored evidence
Original CVE published: 2024-04-18
Original CVE updated: 2024-04-30
Advisory published: 2024-04-18
Advisory updated: 2024-04-30

Who should care

Industrial control system operators, OT security teams, manufacturing security personnel, critical infrastructure defenders, and organizations using Unitronics Vision Legacy PLCs in production environments should prioritize assessment and mitigation of this vulnerability.

Technical summary

The Unitronics Vision Legacy series PLCs expose the 'Information Mode' password in plaintext to remote, unauthenticated attackers. This password disclosure vulnerability enables unauthorized individuals to gain administrative access to PLC configuration and operational parameters. The attack requires network access to the PLC, typically via TCP/20256 (default programmer port). The vulnerability affects all versions of five PLC models: Vision 120, 230, 280, 290, and 530. No patch is available; mitigation relies on configuration changes and network access controls.

Defensive priority

HIGH

Recommended defensive actions

Change the default 'Info Mode' password (1111) via system integer SI 253 on affected PLCs
Restrict Ethernet access to PLCs with Ethernet cards by implementing PLC multi-factor access using SB 314
Apply multi-factor VPN protection for remote access to PLC services
Restrict access to TCP/20256 by changing the default programmer port or applying multi-factor VPN protection
Follow Unitronics published recommendations or contact Unitronics technical support for additional guidance
Apply network segmentation to isolate affected PLCs from untrusted networks
Monitor for unauthorized access attempts on TCP/20256 and PLC management interfaces

Evidence notes

Source: CISA CSAF advisory ICSA-24-109-01. CVSS 3.1 vector: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Affected products confirmed via CSAF product tree: Vision 230, 280, 290, 530, 120 (all versions). Vendor mitigations added in Update A (April 30, 2024).

Official resources

CISA ICS Advisory ICSA-24-109-01, published April 18, 2024; Update A published April 30, 2024