BrightSign Digital Signage Diagnostic Web Server 8.2.26 Unauthenticated SSRF


Vendor: BrightSign, LLC
Product web page: https://www.brightsign.biz
Affected version: Model: XT, XD, HD, LS
                  Firmware / OS version: <=8.2.26


Summary: BrightSign designs media players and provides free software
and cloud networking solutions for the commercial digital signage market
worldwide, serving all vertical segments of the marketplace.

Desc: Unauthenticated Server-Side Request Forgery (SSRF) vulnerability
exists in the BrightSign digital signage media player affecting the
Diagnostic Web Server (DWS). The application parses user supplied data
in the 'url' GET parameter to construct a diagnostics request to the
Download Speed Test service. Since no validation is carried out on the
parameter, an attacker can specify an external domain and force the
application to make an HTTP request to an arbitrary destination host.
This can be used by an external attacker for example to bypass firewalls
and initiate a service and network enumeration on the internal network
through the affected application.

Tested on: roNodeJS


Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                            @zeroscience


Advisory ID: ZSL-2020-5595
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2020-5595.php


01.08.2020

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PoC:

# curl http://10.0.0.17/speedtest?url=127.0.0.1:22