Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/7a3c4ec00ba952207f25d1189c86ce22.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: IRC-Worm.Win32.Silentium.a
Vulnerability: Insecure Permissions 
Description: Silentium.a creates an insecure dir named "Games" 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: 7a3c4ec00ba952207f25d1189c86ce22
Vuln ID: MVID-2021-0153
Dropped files: svchost.exe
Disclosure: 03/30/2021


Exploit/PoC:
C:\>cacls Games
C:\Games 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 Games

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

 Directory of C:\Games

06/14/2012  06:08 PM            20,480 svchost.exe
               1 File(s)         20,480 bytes


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