Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/0b3c2053a7c09aa25ba81f2bdebbb873.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Worm.Win32.Ngrbot.acno
Vulnerability: Insecure Permissions
Description: Creates a dir named "ffffd76" under c:\ drive and grants change (C) permissions to the authenticated user group. Standard users can rename the executables 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: 0b3c2053a7c09aa25ba81f2bdebbb873
Vuln ID: MVID-2021-0144
Dropped files: ffffd76.exe
Disclosure: 03/24/2021


Exploit/PoC:
C:\>cacls ffffd76
C:\ffffd76 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:\>cd ffffd76

C:\ffffd76>dir
 Volume in drive C has no label.

 Directory of C:\ffffd76

03/24/2021  12:20 AM           215,552 ffffd76.exe
               1 File(s)        215,552 bytes
               0 Dir(s)  15,931,383,808 bytes free


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