Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/304fb160949dcaec3e718481464f9ce6.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Trojan.Win32.Banpak.kh
Vulnerability: Insecure Permissions
Description: The malware creates a dir with insecure permissions under c:\ drive and grants change (C) permissions to the authenticated user group. Standard users can rename the executable dropped by the malware to disable it or replace it with their own executable. Then wait for a privileged user to logon to the infected machine to potentially escalate privileges.
Type: PE32
MD5: 304fb160949dcaec3e718481464f9ce6
Vuln ID: MVID-2021-0258
Dropped files: taskhostoy.exe, vp8encoder.dll
Disclosure: 06/23/2021


Exploit/PoC:
C:\>cacls ZpaTo68.tmp
C:\ZpaTo68.tmp 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:\>dir /a ZpaTo68.tmp
 Volume in drive C has no label.

 Directory of C:\ZpaTo68.tmp

10/10/2017  04:44 AM         4,570,112 taskhostoy.exe
06/17/2021  2:33 AM         1,639,336 vp8encoder.dll
               2 File(s)      6,209,448 bytes


Disclaimer: The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. Do not attempt to download Malware samples. The author of this website takes no responsibility for any kind of damages occurring from improper Malware handling or the downloading of ANY Malware mentioned on this website or elsewhere. All content Copyright (c) Malvuln.com (TM).