ShoprLynx 9.2.3 Insecure File Permissions

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ShaprLynx v9.2.3 Insecure File Permissions  
  
  
Vendor: Lynx Software Pty Ltd.  
Product web page: https://www.sharplynx.com  
Affected version: 9.02.0003  
  
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.  
  
Desc: 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.  
  
Tested on: Microsoft Windows 7 Professional SP1 (EN)  
  
  
Vulnerability discovered by Gjoko 'LiquidWorm' Krstic  
@zeroscience  
  
  
Advisory ID: ZSL-2018-5456  
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2018-5456.php  
  
  
27.03.2018  
  
--  
  
  
C:\>cacls "Lynx Software"  
C:\Lynx Software BUILTIN\Administrators:(ID)F  
BUILTIN\Administrators:(OI)(CI)(IO)(ID)F  
NT AUTHORITY\SYSTEM:(ID)F  
NT AUTHORITY\SYSTEM:(OI)(CI)(IO)(ID)F  
BUILTIN\Users:(OI)(CI)(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(ID)C  
  
  
C:\Lynx Software\SharpLynx v9>dir *.exe  
Volume in drive C has no label.  
Volume Serial Number is 54D3-A5E6  
  
Directory of C:\Lynx Software\SharpLynx v9  
  
02/22/2018 02:23 PM 527,840 SL.exe  
02/22/2018 02:23 PM 6,747,104 SLE.exe  
02/22/2018 02:23 PM 6,747,104 SLED.exe  
02/22/2018 02:23 PM 6,747,104 SLER.exe  
02/22/2018 02:23 PM 4,932,064 SLU.exe  
02/22/2018 02:23 PM 4,932,064 SLUR.exe  
07/15/2016 05:58 PM 7,590,288 TeamViewerQS_en.exe  
7 File(s) 38,223,568 bytes  
0 Dir(s) 2,677,899,264 bytes free  
  
C:\Lynx Software\SharpLynx v9>cacls *.exe  
C:\Lynx Software\SharpLynx v9\SL.exe BUILTIN\Administrators:(ID)F  
NT AUTHORITY\SYSTEM:(ID)F  
BUILTIN\Users:(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
  
C:\Lynx Software\SharpLynx v9\SLE.exe BUILTIN\Administrators:(ID)F  
NT AUTHORITY\SYSTEM:(ID)F  
BUILTIN\Users:(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
  
C:\Lynx Software\SharpLynx v9\SLED.exe BUILTIN\Administrators:(ID)F  
NT AUTHORITY\SYSTEM:(ID)F  
BUILTIN\Users:(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
  
C:\Lynx Software\SharpLynx v9\SLER.exe BUILTIN\Administrators:(ID)F  
NT AUTHORITY\SYSTEM:(ID)F  
BUILTIN\Users:(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
  
C:\Lynx Software\SharpLynx v9\SLU.exe BUILTIN\Administrators:(ID)F  
NT AUTHORITY\SYSTEM:(ID)F  
BUILTIN\Users:(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
  
C:\Lynx Software\SharpLynx v9\SLUR.exe BUILTIN\Administrators:(ID)F  
NT AUTHORITY\SYSTEM:(ID)F  
BUILTIN\Users:(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
  
C:\Lynx Software\SharpLynx v9\TeamViewerQS_en.exe BUILTIN\Administrators:(ID)F  
NT AUTHORITY\SYSTEM:(ID)F  
BUILTIN\Users:(ID)R  
NT AUTHORITY\Authenticated Use  
rs:(ID)C  
  
  
C:\Lynx Software\SharpLynx v9>icacls SLE.exe  
SLE.exe BUILTIN\Administrators:(I)(F)  
NT AUTHORITY\SYSTEM:(I)(F)  
BUILTIN\Users:(I)(RX)  
NT AUTHORITY\Authenticated Users:(I)(M)  
  
Successfully processed 1 files; Failed processing 0 files  
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