Sielco PolyEco Digital FM Transmitter 2.0.6 Authentication Bypass Exploit

Title: Sielco PolyEco Digital FM Transmitter 2.0.6 Authentication Bypass Exploit
Advisory ID: ZSL-2023-5769
Type: Local/Remote
Impact: Privilege Escalation, Security Bypass, System Access
Risk: (5/5)
Release Date: 10.04.2023
PolyEco is the innovative family of high-end digital FM transmitters of Sielco. They are especially suited as high performance power system exciters or compact low-mid power transmitters. The same cabinet may in fact be fitted with 50, 100, 300, 500, 1000W power stage (PolyEco50, 100, 300, 500, 1000).

All features can be controlled via the large touch-screen display 4.3" or remotely. Many advanced features are inside by default in the basic version such as: stereo and RDS encoder, audio change-over, remote-control via LAN and SNMP, "FFT" spectral analysis of the audio sources, SFN synchronization and much more.
The application suffers from an authentication bypass and account takeover/lockout vulnerability that can be triggered by directly calling the users object and effectively modifying the password of the two constants user/role (user/admin). This can be exploited by an unauthenticated adversary by issuing a single POST request to the vulnerable endpoint and gain unauthorized access to the affected device with administrative privileges.
Sielco S.r.l -
Affected Version
PolyEco1000 CPU:2.0.6 FPGA:10.19
PolyEco1000 CPU:1.9.4 FPGA:10.19
PolyEco1000 CPU:1.9.3 FPGA:10.19
PolyEco500 CPU:1.7.0 FPGA:10.16
PolyEco300 CPU:2.0.2 FPGA:10.19
PolyEco300 CPU:2.0.0 FPGA:10.19
Tested On
lwIP/2.1.1 (
Vendor Status
[26.01.2023] Vulnerability discovered.
[27.01.2023] Contact with the vendor and CSIRT Italia.
[09.04.2023] No response from the vendor.
[09.04.2023] No response from the CSIRT team.
[10.04.2023] Public security advisory released.
Vulnerability discovered by Gjoko Krstic - <>
[10.04.2023] - Initial release
[03.11.2023] - Added reference [1], [2], [3], [4], [5], [6], [7], [8] and [9]
Zero Science Lab