Title: ABB Cylon FLXeon 9.3.4 (upload.js) Authenticated Root Remote Code Execution
Advisory ID: ZSL-2025-5909
Type: Local/Remote
Impact: System Access, DoS
Risk: (5/5)
Release Date: 02.02.2025

Summary

BACnet® Smart Building Controllers. ABB's BACnet portfolio features a series of BACnet® IP and BACnet MS/TP field controllers for ASPECT® and INTEGRA™ building management solutions. ABB BACnet controllers are designed for intelligent control of HVAC equipment such as central plant, boilers, chillers, cooling towers, heat pump systems, air handling units (constant volume, variable air volume, and multi-zone), rooftop units, electrical systems such as lighting control, variable frequency drives and metering.

The FLXeon Controller Series uses BACnet/IP standards to deliver unprecedented connectivity and open integration for your building automation systems. It's scalable, and modular, allowing you to control a diverse range of HVAC functions.

Description

The ABB Cylon FLXeon BACnet controller is vulnerable to an authenticated root command injection. An attacker can exploit the Backup-Restore feature via the /api/upload endpoint to execute arbitrary system commands as root. The issue arises due to improper input validation in upload.js, where user-supplied input is passed to ChildProcess.exec() without adequate sanitization, allowing command injection via the filename parameter.

Vendor

ABB Ltd. - https://www.global.abb

Affected Version

FLXeon Series (FBXi Series, FBTi Series, FBVi Series)
CBX Series (FLX Series)
CBT Series
CBV Series
Firmware: <=9.3.4

Tested On

Linux Kernel 5.4.27
Linux Kernel 4.15.13
NodeJS/8.4.0
Express

Vendor Status

[21.04.2024] Vulnerability discovered.
[22.04.2024] Vendor contacted.
[22.04.2024] Vendor responds.
[02.05.2024] Working with the vendor.
[20.01.2025] Vendor releases version 9.3.5 to address this issue.
[02.02.2025] Coordinated public security advisory released.

PoC

abb_flxeon_rce3.txt

Credits

Vulnerability discovered by Gjoko Krstic - <gjoko@zeroscience.mk>

References

[1] https://search.abb.com/library/Download.aspx?DocumentID=9AKK108470A5684&LanguageCode=en&DocumentPartId=PDF&Action=Launch
[2] https://www.cve.org/CVERecord?id=CVE-2024-48841
[3] https://packetstorm.news/files/id/188962/

Changelog

[02.02.2025] - Initial release
[03.02.2025] - Added reference [3]

Contact

Zero Science Lab

Web: https://www.zeroscience.mk
e-mail: lab@zeroscience.mk