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SharpLynx v9.2.3 Insecure File Permissions

Medium
Advisory ID
ZSL-2018-5456
Release Date
02 April 2018
Vendor
Lynx Software Pty Ltd. - https://www.sharplynx.com
Affected Version
9.02.0003
CVE
N/A
Tested On
Microsoft Windows 7 Professional SP1 (EN)
Summary

Back Office Software for Sharp POS Terminals. Catering for the needs of retail and hospitality businesses, SharpLynx has been developed as a modular software solution with options from simple program management and sales analysis through to multi-location stock control.

Description

SharpLynx suffers from an elevation of privileges vulnerability which can be used by a simple authenticated user that can change the executable file with a binary of choice. The vulnerability exist due to the improper permissions, with the 'C' flag (Change) for 'Authenticated Users' group.

Proof of Concept
Disclosure Timeline
27.03.2018Vulnerability discovered.
28.03.2018Vendor contacted.
01.04.2018No response from the vendor.
02.04.2018Public security advisory released.
Credits
Vulnerability discovered by Gjoko Krstic
References
Changelog
02.04.2018Initial release
08.04.2018Added reference [1] and [2]
16.04.2018Added reference [3]