Sielco PolyEco Digital FM Transmitter 2.0.6 Authentication Bypass

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Sielco PolyEco Digital FM Transmitter 2.0.6 Account Takeover / Lockout / EoP  
  
  
Vendor: Sielco S.r.l  
Product web page: https://www.sielco.org  
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  
  
Summary: 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.  
  
Desc: The application suffers from an authentication bypass,  
account takeover/lockout and elevation of privileges 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.  
  
Tested on: lwIP/2.1.1 (http://savannah.nongnu.org/projects/lwip)  
  
  
Vulnerability discovered by Gjoko 'LiquidWorm' Krstic  
Macedonian Information Security Research and Development Laboratory  
Zero Science Lab - https://www.zeroscience.mk - @zeroscience  
  
  
Advisory ID: ZSL-2023-5765  
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2023-5765.php  
  
  
26.01.2023  
  
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# Change admin pwd  
$ curl -X POST -F "pwd_admin=t00t" -F "pwd_user=" http://RADIOFM/protect/users.htm  
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