Sielco PolyEco Digital FM Transmitter 2.0.6 'polyeco' Session Hijacking


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 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.

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-2023-5763
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2023-5763.php


26.01.2023

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# Session values (len=5)

Cookie: polyeco=23770
Cookie: polyeco=12397
Cookie: polyeco=54689
...


# GET request for login (user:1234)

http://RADIOFM/login.cgi?user=user&password=c494fe7ab21e23e456a89d5a09828a10&id=14810

The hash = password + id = 123414810, md5(123414810) = c494fe7ab21e23e456a89d5a09828a10

Once authenticated, Cookie: polyeco=14810