Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/46e27d7bfdbda7a71dfa12a79026a88b.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Worm.Win32.Delf.hu
Vulnerability: Insecure Permissions
Description: The malware creates a hidden insecure dir named "RECYCLER" 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: 46e27d7bfdbda7a71dfa12a79026a88b
Vuln ID: MVID-2021-0192
Dropped ok.exe, REM.com
Disclosure: 04/29/2021

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

 Directory of C:\RECYCLER

06/16/2012  12:21 AM           449,024 ok.exe
06/16/2012  09:55 AM            61,952 REM.com
               2 File(s)        510,976 bytes
               2 Dir(s)  23,871,930,368 bytes free

C:\>cacls RECYCLER
C:\RECYCLER 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


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