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ZKTeco ZKAccess Professional 3.5.3 Insecure File Permissions

Low
Advisory ID
ZSL-2016-5361
Release Date
30 August 2016
Vendor
ZKTeco Inc. - http://www.zkteco.com
Affected Version
3.5.3 (Build 0005)
Tested On
Microsoft Windows 7 Ultimate SP1 (EN), Microsoft Windows 7 Professional SP1 (EN)
Summary

ZKAccess 3.5 is a desktop software which is suitable for small and medium businesses application. Compatible with all ZKAccess standalone reader controllers, the software can simultaneously manage access control and generate attendance report. The brand new flat GUI design and humanized structure of new ZKAccess 3.5 will make your daily management more pleasant and convenient.

Description

ZKAccess 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 'M' flag (Modify) for 'Authenticated Users' group.

Proof of Concept
Disclosure Timeline
18.07.2016Vulnerability discovered.
27.07.2016Vendor contacted.
29.08.2016No response from the vendor.
30.08.2016Public security advisory released.
Credits
Vulnerability discovered by Gjoko Krstic
References
Changelog
30.08.2016Initial release
26.09.2016Added reference [1], [2], [3] and [4]
24.03.2026Added reference [5]