Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/10550ca42c32c22bdd0515020cff38dd.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Trojan.Win32.VB.bcng
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: 10550ca42c32c22bdd0515020cff38dd
Vuln ID: MVID-2021-0272
Dropped files: logs.exe, Trojan.Win32.VB.bcng.10550ca42c32c22bdd0515020cff38ddCMD.bat, Trojan.Win32.VB.bcng.10550ca42c32c22bdd0515020cff38ddMuC.bat
Disclosure: 07/03/2021

Exploit/PoC:
C:\>cacls .exe
C:\.exe BUILTIN\Administrators:(ID)F
        NT AUTHORITY\SYSTEM:(ID)F
        BUILTIN\Users:(ID)R
        NT AUTHORITY\Authenticated Users:(ID)C


C:\>cacls Intel
C:\Intel 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 Intel\logs
 Volume in drive C has no label.

 Directory of C:\Intel\logs

07/13/2012  02:52 AM           274,432 logs.exe
               1 File(s)        274,432 bytes
               3 Dir(s)   7,953,518,592 bytes free

C:\>dir Intel\logs\Chip
 Volume in drive C has no label.

 Directory of C:\Intel\logs\Chip

06/28/2021  03:29 AM               988 Trojan.Win32.VB.bcng.10550ca42c32c22bdd0515020cff38ddCMD.bat
06/28/2021  03:29 AM               310 Trojan.Win32.VB.bcng.10550ca42c32c22bdd0515020cff38ddMuC.bat
               2 File(s)          1,298 bytes


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