Meinberg LANTIME Web Configuration Utility 6.16.008 - Arbitrary File Read

Title: Meinberg LANTIME Web Configuration Utility - Arbitrary File Read
Author: Jakub Palaczynski
CVE: CVE-2017-16787


Exploit tested on:
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Meinberg LANTIME Web Configuration Utility 6.16.008


Vulnerability affects:
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All LTOS6 firmware releases before 6.24.004


Vulnerability:
**************

Arbitrary File Read:
====================

It is possible to read arbitrary file on the system with root permissions

Proof of Concept:
First instance:
https://host/cgi-bin/mainv2?value=800&showntpclientipinfo=xxx&ntpclientcounterlogfile=/etc/passwd&lcs=xxx
Info-User user is able to read any file on the system with root permissions.

Second instance:
User with Admin-User access is able to read any file on the system via
firmware update functionality. Curl accepts "file" schema which actually
downloads file from the filesystem. Then it is possible to download
/upload/update file which contains content of requested file.

Contact:
========

Jakub[dot]Palaczynski[at]gmail[dot]com