Headline
ABB Cylon FLXeon 9.3.5 (siteGuide.js) Authenticated Root Remote Code Execution
The ABB Cylon FLXeon BACnet controller is vulnerable to authenticated remote root code execution via the /api/siteGuide endpoint. An attacker with valid credentials can inject arbitrary system commands by manipulating the filename and/or originalname parameters. The issue arises due to improper input validation in siteGuide.js, where user-supplied data is executed via ChildProcess.exec() without adequate sanitization.
Title: ABB Cylon FLXeon 9.3.5 (siteGuide.js) Authenticated Root Remote Code Execution
Advisory ID: ZSL-2025-5932
Type: Local/Remote
Impact: System Access, DoS
Risk: (4/5)
Release Date: 19.05.2025
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 authenticated remote root code execution via the /api/siteGuide endpoint. An attacker with valid credentials can inject arbitrary system commands by manipulating the filename and/or originalname parameters. The issue arises due to improper input validation in siteGuide.js, where user-supplied data is executed via ChildProcess.exec() without adequate sanitization.
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: <=9.3.5
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.
[18.05.2025] No response from the vendor.
[19.05.2025] Public security advisory released.
PoC
abb_flxeon_rce7.txt
Credits
Vulnerability discovered by Gjoko Krstic - <[email protected]>
References
[1] https://packetstorm.news/files/id/193137/
Changelog
[19.05.2025] - Initial release
Contact
Zero Science Lab
Web: https://www.zeroscience.mk
e-mail: [email protected]