Backdoor.Win32.Bifrose.ahyg Insecure Permissions

`Discovery / credits: Malvuln - malvuln.com (c) 2021  
Original source: https://malvuln.com/advisory/d6aff119c03ff378d386b30b36b07a69.txt  
Contact: [email protected]  
Media: twitter.com/malvuln  
  
Threat: Backdoor.Win32.Bifrose.ahyg  
Vulnerability: Insecure Permissions  
Description: The malware creates an dir with insecure permissions under c:\ drive granting 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: d6aff119c03ff378d386b30b36b07a69  
Vuln ID: MVID-2021-0356  
Dropped files: vfenr522008a.exe  
Disclosure: 10/04/2021  
  
Exploit/PoC:  
C:\>cacls Temp  
C:\Temp 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 Temp  
Volume in drive C has no label.  
  
Directory of C:\Temp  
  
10/03/2021 01:40 AM 689,664 vfenr522008a.exe  
1 File(s) 689,664 bytes  
  
  
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