Discovery / credits: malvuln - Malvuln.com (c) 2021
Original source: http://malvuln.com/advisory/82183b3d85311a39fb80ae07357594e5.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: BACKDOOR.WIN32.REMOTEMANIPULATOR
Vulnerability: Insecure Permissions
Description: Creates a dir Folder139 with insecure permissions as it hands authenticated users change permissions (C). The backdoor drops an EXE named audiohd.exe which is not visible unless viewing using dir /a command. There we find the exeuctable audiohd.exe and another hidden DLL vp8encoder.dll

Type: PE32
MD5: 82183b3d85311a39fb80ae07357594e5
Vuln ID: MVID-2021-0005
Dropped files: audiohd.exe, vp8encoder.dll
Disclosure: 01/01/2021

Exploit/PoC: 
C:\>cacls C:\Folder139
C:\Folder139 BUILTIN\Administrators:(OI)(CI)(ID)F
             NT AUTHORITY\SYSTEM:(OI)(CI)(ID)F
             BUILTIN\Users:(OI)(CI)(ID)R
             NT AUTHORITY\Authenticated Users:(ID)C
             NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(ID)C

C:\Folder139>dir /a

02/15/2017  09:51 AM        1,486,848 audiohd.exe
07/15/2015  08:19 PM        607,440 vp8encoder.dll


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