Sielco PolyEco Digital FM Transmitter 2.0.6 'polyeco' Session Hijacking

Title: Sielco PolyEco Digital FM Transmitter 2.0.6 'polyeco' Session Hijacking
Advisory ID: ZSL-2023-5763
Type: Local/Remote
Impact: Security Bypass
Risk: (4/5)
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 Cookie 'polyeco' is of an insufficient length and can be exploited by brute force, which may allow a remote attacker to obtain a valid session, bypass authentication and manipulate the transmitter. The session is also visible in an HTTP GET request and there is the lack of SSL in use, allowing MitM attacks.
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] and [6]
Zero Science Lab